From 4fbb48cb110be653adcd97a87506e0ba8c16d585 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 30 Apr 2014 22:35:48 -0400 Subject: ftrace: Allow no regs if no more callbacks require it When registering a function callback for the function tracer, the ops can specify if it wants to save full regs (like an interrupt would) for each function that it traces, or if it does not care about regs and just wants to have the fastest return possible. Once a ops has registered a function, if other ops register that function they all will receive the regs too. That's because it does the work once, it does it for everyone. Now if the ops wanting regs unregisters the function so that there's only ops left that do not care about regs, those ops will still continue getting regs and going through the work for it on that function. This is because the disabling of the rec counter only sees the ops registered, and does not see the ops that are still attached, and does not know if the current ops that are still attached want regs or not. To play it safe, it just keeps regs being processed until no function is registered anymore. Instead of doing that, check the ops that are still registered for that function and if none want regs for it anymore, then disable the processing of regs. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5b372e3ed675..b867c647e5bc 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1492,6 +1492,26 @@ int ftrace_text_reserved(const void *start, const void *end) return (int)!!ret; } +/* Test if ops registered to this rec needs regs */ +static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) +{ + struct ftrace_ops *ops; + bool keep_regs = false; + + for (ops = ftrace_ops_list; + ops != &ftrace_list_end; ops = ops->next) { + /* pass rec in as regs to have non-NULL val */ + if (ftrace_ops_test(ops, rec->ip, rec)) { + if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) { + keep_regs = true; + break; + } + } + } + + return keep_regs; +} + static void __ftrace_hash_rec_update(struct ftrace_ops *ops, int filter_hash, bool inc) @@ -1584,6 +1604,18 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0)) return; rec->flags--; + /* + * If the rec had REGS enabled and the ops that is + * being removed had REGS set, then see if there is + * still any ops for this record that wants regs. + * If not, we can stop recording them. + */ + if ((rec->flags & ~FTRACE_FL_MASK) > 0 && + rec->flags & FTRACE_FL_REGS && + ops->flags & FTRACE_OPS_FL_SAVE_REGS) { + if (!test_rec_ops_needs_regs(rec)) + rec->flags &= ~FTRACE_FL_REGS; + } } count++; /* Shortcut, if we handled all records, we are done. */ -- cgit v1.2.3 From 0376bde11be5b87c9fd7d6813ac5fd7e1798b1bf Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 7 May 2014 13:46:45 -0400 Subject: ftrace: Add ftrace_rec_counter() macro to simplify the code The ftrace dynamic record has a flags element that also has a counter. Instead of hard coding "rec->flags & ~FTRACE_FL_MASK" all over the place. Use a macro instead. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index b867c647e5bc..a58d840305c3 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1592,7 +1592,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (inc) { rec->flags++; - if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == FTRACE_REF_MAX)) + if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return; /* * If any ops wants regs saved for this function @@ -1601,7 +1601,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (ops->flags & FTRACE_OPS_FL_SAVE_REGS) rec->flags |= FTRACE_FL_REGS; } else { - if (FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0)) + if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) return; rec->flags--; /* @@ -1610,7 +1610,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, * still any ops for this record that wants regs. * If not, we can stop recording them. */ - if ((rec->flags & ~FTRACE_FL_MASK) > 0 && + if (ftrace_rec_count(rec) > 0 && rec->flags & FTRACE_FL_REGS && ops->flags & FTRACE_OPS_FL_SAVE_REGS) { if (!test_rec_ops_needs_regs(rec)) @@ -1700,7 +1700,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) * If we are disabling calls, then disable all records that * are enabled. */ - if (enable && (rec->flags & ~FTRACE_FL_MASK)) + if (enable && ftrace_rec_count(rec)) flag = FTRACE_FL_ENABLED; /* @@ -1746,7 +1746,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) if (update) { /* If there's no more users, clear all flags */ - if (!(rec->flags & ~FTRACE_FL_MASK)) + if (!ftrace_rec_count(rec)) rec->flags = 0; else /* Just disable the record (keep REGS state) */ @@ -2685,7 +2685,7 @@ static int t_show(struct seq_file *m, void *v) seq_printf(m, "%ps", (void *)rec->ip); if (iter->flags & FTRACE_ITER_ENABLED) seq_printf(m, " (%ld)%s", - rec->flags & ~FTRACE_FL_MASK, + ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : ""); seq_printf(m, "\n"); -- cgit v1.2.3 From 79922b8009c074e30d3a97f5a24519f11814ad03 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 6 May 2014 21:56:17 -0400 Subject: ftrace: Optimize function graph to be called directly Function graph tracing is a bit different than the function tracers, as it is processed after either the ftrace_caller or ftrace_regs_caller and we only have one place to modify the jump to ftrace_graph_caller, the jump needs to happen after the restore of registeres. The function graph tracer is dependent on the function tracer, where even if the function graph tracing is going on by itself, the save and restore of registers is still done for function tracing regardless of if function tracing is happening, before it calls the function graph code. If there's no function tracing happening, it is possible to just call the function graph tracer directly, and avoid the wasted effort to save and restore regs for function tracing. This requires adding new flags to the dyn_ftrace records: FTRACE_FL_TRAMP FTRACE_FL_TRAMP_EN The first is set if the count for the record is one, and the ftrace_ops associated to that record has its own trampoline. That way the mcount code can call that trampoline directly. In the future, trampolines can be added to arbitrary ftrace_ops, where you can have two or more ftrace_ops registered to ftrace (like kprobes and perf) and if they are not tracing the same functions, then instead of doing a loop to check all registered ftrace_ops against their hashes, just call the ftrace_ops trampoline directly, which would call the registered ftrace_ops function directly. Without this patch perf showed: 0.05% hackbench [kernel.kallsyms] [k] ftrace_caller 0.05% hackbench [kernel.kallsyms] [k] arch_local_irq_save 0.05% hackbench [kernel.kallsyms] [k] native_sched_clock 0.04% hackbench [kernel.kallsyms] [k] __buffer_unlock_commit 0.04% hackbench [kernel.kallsyms] [k] preempt_trace 0.04% hackbench [kernel.kallsyms] [k] prepare_ftrace_return 0.04% hackbench [kernel.kallsyms] [k] __this_cpu_preempt_check 0.04% hackbench [kernel.kallsyms] [k] ftrace_graph_caller See that the ftrace_caller took up more time than the ftrace_graph_caller did. With this patch: 0.05% hackbench [kernel.kallsyms] [k] __buffer_unlock_commit 0.04% hackbench [kernel.kallsyms] [k] call_filter_check_discard 0.04% hackbench [kernel.kallsyms] [k] ftrace_graph_caller 0.04% hackbench [kernel.kallsyms] [k] sched_clock The ftrace_caller is no where to be found and ftrace_graph_caller still takes up the same percentage. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 242 ++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 235 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a58d840305c3..5d15eb8146a7 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1042,6 +1042,8 @@ static struct pid * const ftrace_swapper_pid = &init_struct_pid; #ifdef CONFIG_DYNAMIC_FTRACE +static struct ftrace_ops *removed_ops; + #ifndef CONFIG_FTRACE_MCOUNT_RECORD # error Dynamic ftrace depends on MCOUNT_RECORD #endif @@ -1512,6 +1514,33 @@ static bool test_rec_ops_needs_regs(struct dyn_ftrace *rec) return keep_regs; } +static void ftrace_remove_tramp(struct ftrace_ops *ops, + struct dyn_ftrace *rec) +{ + struct ftrace_func_entry *entry; + + entry = ftrace_lookup_ip(ops->tramp_hash, rec->ip); + if (!entry) + return; + + /* + * The tramp_hash entry will be removed at time + * of update. + */ + ops->trampolines--; + rec->flags &= ~FTRACE_FL_TRAMP; +} + +static void ftrace_clear_tramps(struct dyn_ftrace *rec) +{ + struct ftrace_ops *op; + + do_for_each_ftrace_op(op, ftrace_ops_list) { + if (op->trampolines) + ftrace_remove_tramp(op, rec); + } while_for_each_ftrace_op(op); +} + static void __ftrace_hash_rec_update(struct ftrace_ops *ops, int filter_hash, bool inc) @@ -1594,6 +1623,28 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, rec->flags++; if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return; + + /* + * If there's only a single callback registered to a + * function, and the ops has a trampoline registered + * for it, then we can call it directly. + */ + if (ftrace_rec_count(rec) == 1 && ops->trampoline) { + rec->flags |= FTRACE_FL_TRAMP; + ops->trampolines++; + } else { + /* + * If we are adding another function callback + * to this function, and the previous had a + * trampoline used, then we need to go back to + * the default trampoline. + */ + rec->flags &= ~FTRACE_FL_TRAMP; + + /* remove trampolines from any ops for this rec */ + ftrace_clear_tramps(rec); + } + /* * If any ops wants regs saved for this function * then all ops will get saved regs. @@ -1604,6 +1655,10 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (FTRACE_WARN_ON(ftrace_rec_count(rec) == 0)) return; rec->flags--; + + if (ops->trampoline && !ftrace_rec_count(rec)) + ftrace_remove_tramp(ops, rec); + /* * If the rec had REGS enabled and the ops that is * being removed had REGS set, then see if there is @@ -1616,6 +1671,11 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, if (!test_rec_ops_needs_regs(rec)) rec->flags &= ~FTRACE_FL_REGS; } + + /* + * flags will be cleared in ftrace_check_record() + * if rec count is zero. + */ } count++; /* Shortcut, if we handled all records, we are done. */ @@ -1704,13 +1764,19 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) flag = FTRACE_FL_ENABLED; /* - * If enabling and the REGS flag does not match the REGS_EN, then - * do not ignore this record. Set flags to fail the compare against - * ENABLED. + * If enabling and the REGS flag does not match the REGS_EN, or + * the TRAMP flag doesn't match the TRAMP_EN, then do not ignore + * this record. Set flags to fail the compare against ENABLED. */ - if (flag && - (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN))) - flag |= FTRACE_FL_REGS; + if (flag) { + if (!(rec->flags & FTRACE_FL_REGS) != + !(rec->flags & FTRACE_FL_REGS_EN)) + flag |= FTRACE_FL_REGS; + + if (!(rec->flags & FTRACE_FL_TRAMP) != + !(rec->flags & FTRACE_FL_TRAMP_EN)) + flag |= FTRACE_FL_TRAMP; + } /* If the state of this record hasn't changed, then do nothing */ if ((rec->flags & FTRACE_FL_ENABLED) == flag) @@ -1728,6 +1794,12 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) else rec->flags &= ~FTRACE_FL_REGS_EN; } + if (flag & FTRACE_FL_TRAMP) { + if (rec->flags & FTRACE_FL_TRAMP) + rec->flags |= FTRACE_FL_TRAMP_EN; + else + rec->flags &= ~FTRACE_FL_TRAMP_EN; + } } /* @@ -1736,7 +1808,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update) * Otherwise, * return UPDATE_MODIFY_CALL to tell the caller to convert * from the save regs, to a non-save regs function or - * vice versa. + * vice versa, or from a trampoline call. */ if (flag & FTRACE_FL_ENABLED) return FTRACE_UPDATE_MAKE_CALL; @@ -1783,6 +1855,43 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable) return ftrace_check_record(rec, enable, 0); } +static struct ftrace_ops * +ftrace_find_tramp_ops_curr(struct dyn_ftrace *rec) +{ + struct ftrace_ops *op; + + /* Removed ops need to be tested first */ + if (removed_ops && removed_ops->tramp_hash) { + if (ftrace_lookup_ip(removed_ops->tramp_hash, rec->ip)) + return removed_ops; + } + + do_for_each_ftrace_op(op, ftrace_ops_list) { + if (!op->tramp_hash) + continue; + + if (ftrace_lookup_ip(op->tramp_hash, rec->ip)) + return op; + + } while_for_each_ftrace_op(op); + + return NULL; +} + +static struct ftrace_ops * +ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) +{ + struct ftrace_ops *op; + + do_for_each_ftrace_op(op, ftrace_ops_list) { + /* pass rec in as regs to have non-NULL val */ + if (ftrace_ops_test(op, rec->ip, rec)) + return op; + } while_for_each_ftrace_op(op); + + return NULL; +} + /** * ftrace_get_addr_new - Get the call address to set to * @rec: The ftrace record descriptor @@ -1795,6 +1904,20 @@ int ftrace_test_record(struct dyn_ftrace *rec, int enable) */ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) { + struct ftrace_ops *ops; + + /* Trampolines take precedence over regs */ + if (rec->flags & FTRACE_FL_TRAMP) { + ops = ftrace_find_tramp_ops_new(rec); + if (FTRACE_WARN_ON(!ops || !ops->trampoline)) { + pr_warning("Bad trampoline accounting at: %p (%pS)\n", + (void *)rec->ip, (void *)rec->ip); + /* Ftrace is shutting down, return anything */ + return (unsigned long)FTRACE_ADDR; + } + return ops->trampoline; + } + if (rec->flags & FTRACE_FL_REGS) return (unsigned long)FTRACE_REGS_ADDR; else @@ -1813,6 +1936,20 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) */ unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) { + struct ftrace_ops *ops; + + /* Trampolines take precedence over regs */ + if (rec->flags & FTRACE_FL_TRAMP_EN) { + ops = ftrace_find_tramp_ops_curr(rec); + if (FTRACE_WARN_ON(!ops)) { + pr_warning("Bad trampoline accounting at: %p (%pS)\n", + (void *)rec->ip, (void *)rec->ip); + /* Ftrace is shutting down, return anything */ + return (unsigned long)FTRACE_ADDR; + } + return ops->trampoline; + } + if (rec->flags & FTRACE_FL_REGS_EN) return (unsigned long)FTRACE_REGS_ADDR; else @@ -2055,6 +2192,78 @@ void __weak arch_ftrace_update_code(int command) ftrace_run_stop_machine(command); } +static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops) +{ + struct ftrace_page *pg; + struct dyn_ftrace *rec; + int size, bits; + int ret; + + size = ops->trampolines; + bits = 0; + /* + * Make the hash size about 1/2 the # found + */ + for (size /= 2; size; size >>= 1) + bits++; + + ops->tramp_hash = alloc_ftrace_hash(bits); + /* + * TODO: a failed allocation is going to screw up + * the accounting of what needs to be modified + * and not. For now, we kill ftrace if we fail + * to allocate here. But there are ways around this, + * but that will take a little more work. + */ + if (!ops->tramp_hash) + return -ENOMEM; + + do_for_each_ftrace_rec(pg, rec) { + if (ftrace_rec_count(rec) == 1 && + ftrace_ops_test(ops, rec->ip, rec)) { + + /* This record had better have a trampoline */ + if (FTRACE_WARN_ON(!(rec->flags & FTRACE_FL_TRAMP_EN))) + return -1; + + ret = add_hash_entry(ops->tramp_hash, rec->ip); + if (ret < 0) + return ret; + } + } while_for_each_ftrace_rec(); + + return 0; +} + +static int ftrace_save_tramp_hashes(void) +{ + struct ftrace_ops *op; + int ret; + + /* + * Now that any trampoline is being used, we need to save the + * hashes for the ops that have them. This allows the mapping + * back from the record to the ops that has the trampoline to + * know what code is being replaced. Modifying code must always + * verify what it is changing. + */ + do_for_each_ftrace_op(op, ftrace_ops_list) { + + /* The tramp_hash is recreated each time. */ + free_ftrace_hash(op->tramp_hash); + op->tramp_hash = NULL; + + if (op->trampolines) { + ret = ftrace_save_ops_tramp_hash(op); + if (ret) + return ret; + } + + } while_for_each_ftrace_op(op); + + return 0; +} + static void ftrace_run_update_code(int command) { int ret; @@ -2081,6 +2290,9 @@ static void ftrace_run_update_code(int command) ret = ftrace_arch_code_modify_post_process(); FTRACE_WARN_ON(ret); + + ret = ftrace_save_tramp_hashes(); + FTRACE_WARN_ON(ret); } static ftrace_func_t saved_ftrace_func; @@ -2171,8 +2383,16 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) return 0; } + /* + * If the ops uses a trampoline, then it needs to be + * tested first on update. + */ + removed_ops = ops; + ftrace_run_update_code(command); + removed_ops = NULL; + /* * Dynamic ops may be freed, we must make sure that all * callers are done before leaving this function. @@ -5116,6 +5336,11 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, /* Function graph doesn't use the .func field of global_ops */ global_ops.flags |= FTRACE_OPS_FL_STUB; +#ifdef CONFIG_DYNAMIC_FTRACE + /* Optimize function graph calling (if implemented by arch) */ + global_ops.trampoline = FTRACE_GRAPH_ADDR; +#endif + ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET); out: @@ -5136,6 +5361,9 @@ void unregister_ftrace_graph(void) __ftrace_graph_entry = ftrace_graph_entry_stub; ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET); global_ops.flags &= ~FTRACE_OPS_FL_STUB; +#ifdef CONFIG_DYNAMIC_FTRACE + global_ops.trampoline = 0; +#endif unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); -- cgit v1.2.3 From 9674b2fadab636b1fe27b282f9a9fa0f9d8c9839 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 9 May 2014 16:54:59 -0400 Subject: ftrace: Add trampolines to enabled_functions debug file The enabled_functions is used to help debug the dynamic function tracing. Adding what trampolines are attached to files is useful for debugging. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5d15eb8146a7..3ded796e10e0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2903,10 +2903,22 @@ static int t_show(struct seq_file *m, void *v) return 0; seq_printf(m, "%ps", (void *)rec->ip); - if (iter->flags & FTRACE_ITER_ENABLED) + if (iter->flags & FTRACE_ITER_ENABLED) { seq_printf(m, " (%ld)%s", ftrace_rec_count(rec), - rec->flags & FTRACE_FL_REGS ? " R" : ""); + rec->flags & FTRACE_FL_REGS ? " R" : " "); + if (rec->flags & FTRACE_FL_TRAMP_EN) { + struct ftrace_ops *ops; + + ops = ftrace_find_tramp_ops_curr(rec); + if (ops && ops->trampoline) + seq_printf(m, "\ttramp: %pS", + (void *)ops->trampoline); + else + seq_printf(m, "\ttramp: ERROR!"); + } + } + seq_printf(m, "\n"); return 0; -- cgit v1.2.3 From 5c27c775d5e698d5b754d213747e9fb85290e3b8 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 17 Jun 2014 11:04:42 +0000 Subject: ftrace: Simplify ftrace_hash_disable/enable path in ftrace_hash_move Simplify ftrace_hash_disable/enable path in ftrace_hash_move for hardening the process if the memory allocation failed. Link: http://lkml.kernel.org/p/20140617110442.15167.81076.stgit@kbuild-fedora.novalocal Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 33 +++++++++++---------------------- 1 file changed, 11 insertions(+), 22 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3ded796e10e0..8323082dbc21 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1306,25 +1306,15 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, struct ftrace_hash *new_hash; int size = src->count; int bits = 0; - int ret; int i; - /* - * Remove the current set, update the hash and add - * them back. - */ - ftrace_hash_rec_disable(ops, enable); - /* * If the new source is empty, just free dst and assign it * the empty_hash. */ if (!src->count) { - free_ftrace_hash_rcu(*dst); - rcu_assign_pointer(*dst, EMPTY_HASH); - /* still need to update the function records */ - ret = 0; - goto out; + new_hash = EMPTY_HASH; + goto update; } /* @@ -1337,10 +1327,9 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, if (bits > FTRACE_HASH_MAX_BITS) bits = FTRACE_HASH_MAX_BITS; - ret = -ENOMEM; new_hash = alloc_ftrace_hash(bits); if (!new_hash) - goto out; + return -ENOMEM; size = 1 << src->size_bits; for (i = 0; i < size; i++) { @@ -1351,20 +1340,20 @@ ftrace_hash_move(struct ftrace_ops *ops, int enable, } } +update: + /* + * Remove the current set, update the hash and add + * them back. + */ + ftrace_hash_rec_disable(ops, enable); + old_hash = *dst; rcu_assign_pointer(*dst, new_hash); free_ftrace_hash_rcu(old_hash); - ret = 0; - out: - /* - * Enable regardless of ret: - * On success, we enable the new hash. - * On failure, we re-enable the original hash. - */ ftrace_hash_rec_enable(ops, enable); - return ret; + return 0; } /* -- cgit v1.2.3 From 12306276fabcb746a14979e96f43a13c724dec49 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 20 Jun 2014 13:38:54 -0400 Subject: tracing: Move the trace_seq_* functions into its own trace_seq.c file The trace_seq_*() functions are a nice utility that allows users to manipulate buffers with printf() like formats. It has its own trace_seq.h header in include/linux and should be in its own file. Being tied with trace_output.c is rather awkward. Signed-off-by: Steven Rostedt --- kernel/trace/Makefile | 1 + kernel/trace/trace.c | 24 ---- kernel/trace/trace_output.c | 268 --------------------------------------- kernel/trace/trace_output.h | 3 - kernel/trace/trace_seq.c | 303 ++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 304 insertions(+), 295 deletions(-) create mode 100644 kernel/trace/trace_seq.c (limited to 'kernel') diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile index 2611613f14f1..67d6369ddf83 100644 --- a/kernel/trace/Makefile +++ b/kernel/trace/Makefile @@ -28,6 +28,7 @@ obj-$(CONFIG_RING_BUFFER_BENCHMARK) += ring_buffer_benchmark.o obj-$(CONFIG_TRACING) += trace.o obj-$(CONFIG_TRACING) += trace_output.o +obj-$(CONFIG_TRACING) += trace_seq.o obj-$(CONFIG_TRACING) += trace_stat.o obj-$(CONFIG_TRACING) += trace_printk.o obj-$(CONFIG_CONTEXT_SWITCH_TRACER) += trace_sched_switch.o diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 384ede311717..eeb233cbac4f 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -923,30 +923,6 @@ out: return ret; } -ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) -{ - int len; - int ret; - - if (!cnt) - return 0; - - if (s->len <= s->readpos) - return -EBUSY; - - len = s->len - s->readpos; - if (cnt > len) - cnt = len; - ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); - if (ret == cnt) - return -EFAULT; - - cnt -= ret; - - s->readpos += cnt; - return cnt; -} - static ssize_t trace_seq_to_buffer(struct trace_seq *s, void *buf, size_t cnt) { int len; diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index f3dad80c20b2..b8930f79a04b 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -20,23 +20,6 @@ static struct hlist_head event_hash[EVENT_HASHSIZE] __read_mostly; static int next_event_type = __TRACE_LAST_TYPE + 1; -int trace_print_seq(struct seq_file *m, struct trace_seq *s) -{ - int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; - int ret; - - ret = seq_write(m, s->buffer, len); - - /* - * Only reset this buffer if we successfully wrote to the - * seq_file buffer. - */ - if (!ret) - trace_seq_init(s); - - return ret; -} - enum print_line_t trace_print_bputs_msg_only(struct trace_iterator *iter) { struct trace_seq *s = &iter->seq; @@ -85,257 +68,6 @@ enum print_line_t trace_print_printk_msg_only(struct trace_iterator *iter) return TRACE_TYPE_HANDLED; } -/** - * trace_seq_printf - sequence printing of trace information - * @s: trace sequence descriptor - * @fmt: printf format string - * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * - * The tracer may use either sequence operations or its own - * copy to user routines. To simplify formating of a trace - * trace_seq_printf is used to store strings into a special - * buffer (@s). Then the output may be either used by - * the sequencer or pulled into another buffer. - */ -int -trace_seq_printf(struct trace_seq *s, const char *fmt, ...) -{ - int len = (PAGE_SIZE - 1) - s->len; - va_list ap; - int ret; - - if (s->full || !len) - return 0; - - va_start(ap, fmt); - ret = vsnprintf(s->buffer + s->len, len, fmt, ap); - va_end(ap); - - /* If we can't write it all, don't bother writing anything */ - if (ret >= len) { - s->full = 1; - return 0; - } - - s->len += ret; - - return 1; -} -EXPORT_SYMBOL_GPL(trace_seq_printf); - -/** - * trace_seq_bitmask - put a list of longs as a bitmask print output - * @s: trace sequence descriptor - * @maskp: points to an array of unsigned longs that represent a bitmask - * @nmaskbits: The number of bits that are valid in @maskp - * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * - * Writes a ASCII representation of a bitmask string into @s. - */ -int -trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, - int nmaskbits) -{ - int len = (PAGE_SIZE - 1) - s->len; - int ret; - - if (s->full || !len) - return 0; - - ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); - s->len += ret; - - return 1; -} -EXPORT_SYMBOL_GPL(trace_seq_bitmask); - -/** - * trace_seq_vprintf - sequence printing of trace information - * @s: trace sequence descriptor - * @fmt: printf format string - * - * The tracer may use either sequence operations or its own - * copy to user routines. To simplify formating of a trace - * trace_seq_printf is used to store strings into a special - * buffer (@s). Then the output may be either used by - * the sequencer or pulled into another buffer. - */ -int -trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) -{ - int len = (PAGE_SIZE - 1) - s->len; - int ret; - - if (s->full || !len) - return 0; - - ret = vsnprintf(s->buffer + s->len, len, fmt, args); - - /* If we can't write it all, don't bother writing anything */ - if (ret >= len) { - s->full = 1; - return 0; - } - - s->len += ret; - - return len; -} -EXPORT_SYMBOL_GPL(trace_seq_vprintf); - -int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) -{ - int len = (PAGE_SIZE - 1) - s->len; - int ret; - - if (s->full || !len) - return 0; - - ret = bstr_printf(s->buffer + s->len, len, fmt, binary); - - /* If we can't write it all, don't bother writing anything */ - if (ret >= len) { - s->full = 1; - return 0; - } - - s->len += ret; - - return len; -} - -/** - * trace_seq_puts - trace sequence printing of simple string - * @s: trace sequence descriptor - * @str: simple string to record - * - * The tracer may use either the sequence operations or its own - * copy to user routines. This function records a simple string - * into a special buffer (@s) for later retrieval by a sequencer - * or other mechanism. - */ -int trace_seq_puts(struct trace_seq *s, const char *str) -{ - int len = strlen(str); - - if (s->full) - return 0; - - if (len > ((PAGE_SIZE - 1) - s->len)) { - s->full = 1; - return 0; - } - - memcpy(s->buffer + s->len, str, len); - s->len += len; - - return len; -} - -int trace_seq_putc(struct trace_seq *s, unsigned char c) -{ - if (s->full) - return 0; - - if (s->len >= (PAGE_SIZE - 1)) { - s->full = 1; - return 0; - } - - s->buffer[s->len++] = c; - - return 1; -} -EXPORT_SYMBOL(trace_seq_putc); - -int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) -{ - if (s->full) - return 0; - - if (len > ((PAGE_SIZE - 1) - s->len)) { - s->full = 1; - return 0; - } - - memcpy(s->buffer + s->len, mem, len); - s->len += len; - - return len; -} - -int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) -{ - unsigned char hex[HEX_CHARS]; - const unsigned char *data = mem; - int i, j; - - if (s->full) - return 0; - -#ifdef __BIG_ENDIAN - for (i = 0, j = 0; i < len; i++) { -#else - for (i = len-1, j = 0; i >= 0; i--) { -#endif - hex[j++] = hex_asc_hi(data[i]); - hex[j++] = hex_asc_lo(data[i]); - } - hex[j++] = ' '; - - return trace_seq_putmem(s, hex, j); -} - -void *trace_seq_reserve(struct trace_seq *s, size_t len) -{ - void *ret; - - if (s->full) - return NULL; - - if (len > ((PAGE_SIZE - 1) - s->len)) { - s->full = 1; - return NULL; - } - - ret = s->buffer + s->len; - s->len += len; - - return ret; -} - -int trace_seq_path(struct trace_seq *s, const struct path *path) -{ - unsigned char *p; - - if (s->full) - return 0; - - if (s->len >= (PAGE_SIZE - 1)) { - s->full = 1; - return 0; - } - - p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); - if (!IS_ERR(p)) { - p = mangle_path(s->buffer + s->len, p, "\n"); - if (p) { - s->len = p - s->buffer; - return 1; - } - } else { - s->buffer[s->len++] = '?'; - return 1; - } - - s->full = 1; - return 0; -} - const char * ftrace_print_flags_seq(struct trace_seq *p, const char *delim, unsigned long flags, diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index 127a9d8c8357..bf7daf2237ed 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -35,9 +35,6 @@ trace_print_lat_fmt(struct trace_seq *s, struct trace_entry *entry); extern int __unregister_ftrace_event(struct trace_event *event); extern struct rw_semaphore trace_event_sem; -#define MAX_MEMHEX_BYTES 8 -#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) - #define SEQ_PUT_FIELD_RET(s, x) \ do { \ if (!trace_seq_putmem(s, &(x), sizeof(x))) \ diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c new file mode 100644 index 000000000000..5ba99c6cf834 --- /dev/null +++ b/kernel/trace/trace_seq.c @@ -0,0 +1,303 @@ +/* + * trace_seq.c + * + * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt + * + */ +#include +#include +#include + +int trace_print_seq(struct seq_file *m, struct trace_seq *s) +{ + int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; + int ret; + + ret = seq_write(m, s->buffer, len); + + /* + * Only reset this buffer if we successfully wrote to the + * seq_file buffer. + */ + if (!ret) + trace_seq_init(s); + + return ret; +} + +/** + * trace_seq_printf - sequence printing of trace information + * @s: trace sequence descriptor + * @fmt: printf format string + * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * + * The tracer may use either sequence operations or its own + * copy to user routines. To simplify formating of a trace + * trace_seq_printf is used to store strings into a special + * buffer (@s). Then the output may be either used by + * the sequencer or pulled into another buffer. + */ +int +trace_seq_printf(struct trace_seq *s, const char *fmt, ...) +{ + int len = (PAGE_SIZE - 1) - s->len; + va_list ap; + int ret; + + if (s->full || !len) + return 0; + + va_start(ap, fmt); + ret = vsnprintf(s->buffer + s->len, len, fmt, ap); + va_end(ap); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) { + s->full = 1; + return 0; + } + + s->len += ret; + + return 1; +} +EXPORT_SYMBOL_GPL(trace_seq_printf); + +/** + * trace_seq_bitmask - put a list of longs as a bitmask print output + * @s: trace sequence descriptor + * @maskp: points to an array of unsigned longs that represent a bitmask + * @nmaskbits: The number of bits that are valid in @maskp + * + * It returns 0 if the trace oversizes the buffer's free + * space, 1 otherwise. + * + * Writes a ASCII representation of a bitmask string into @s. + */ +int +trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, + int nmaskbits) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = bitmap_scnprintf(s->buffer, len, maskp, nmaskbits); + s->len += ret; + + return 1; +} +EXPORT_SYMBOL_GPL(trace_seq_bitmask); + +/** + * trace_seq_vprintf - sequence printing of trace information + * @s: trace sequence descriptor + * @fmt: printf format string + * + * The tracer may use either sequence operations or its own + * copy to user routines. To simplify formating of a trace + * trace_seq_printf is used to store strings into a special + * buffer (@s). Then the output may be either used by + * the sequencer or pulled into another buffer. + */ +int +trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = vsnprintf(s->buffer + s->len, len, fmt, args); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) { + s->full = 1; + return 0; + } + + s->len += ret; + + return len; +} +EXPORT_SYMBOL_GPL(trace_seq_vprintf); + +int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) +{ + int len = (PAGE_SIZE - 1) - s->len; + int ret; + + if (s->full || !len) + return 0; + + ret = bstr_printf(s->buffer + s->len, len, fmt, binary); + + /* If we can't write it all, don't bother writing anything */ + if (ret >= len) { + s->full = 1; + return 0; + } + + s->len += ret; + + return len; +} + +/** + * trace_seq_puts - trace sequence printing of simple string + * @s: trace sequence descriptor + * @str: simple string to record + * + * The tracer may use either the sequence operations or its own + * copy to user routines. This function records a simple string + * into a special buffer (@s) for later retrieval by a sequencer + * or other mechanism. + */ +int trace_seq_puts(struct trace_seq *s, const char *str) +{ + int len = strlen(str); + + if (s->full) + return 0; + + if (len > ((PAGE_SIZE - 1) - s->len)) { + s->full = 1; + return 0; + } + + memcpy(s->buffer + s->len, str, len); + s->len += len; + + return len; +} + +int trace_seq_putc(struct trace_seq *s, unsigned char c) +{ + if (s->full) + return 0; + + if (s->len >= (PAGE_SIZE - 1)) { + s->full = 1; + return 0; + } + + s->buffer[s->len++] = c; + + return 1; +} +EXPORT_SYMBOL(trace_seq_putc); + +int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) +{ + if (s->full) + return 0; + + if (len > ((PAGE_SIZE - 1) - s->len)) { + s->full = 1; + return 0; + } + + memcpy(s->buffer + s->len, mem, len); + s->len += len; + + return len; +} + +#define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) + +int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) +{ + unsigned char hex[HEX_CHARS]; + const unsigned char *data = mem; + int i, j; + + if (s->full) + return 0; + +#ifdef __BIG_ENDIAN + for (i = 0, j = 0; i < len; i++) { +#else + for (i = len-1, j = 0; i >= 0; i--) { +#endif + hex[j++] = hex_asc_hi(data[i]); + hex[j++] = hex_asc_lo(data[i]); + } + hex[j++] = ' '; + + return trace_seq_putmem(s, hex, j); +} + +void *trace_seq_reserve(struct trace_seq *s, size_t len) +{ + void *ret; + + if (s->full) + return NULL; + + if (len > ((PAGE_SIZE - 1) - s->len)) { + s->full = 1; + return NULL; + } + + ret = s->buffer + s->len; + s->len += len; + + return ret; +} + +int trace_seq_path(struct trace_seq *s, const struct path *path) +{ + unsigned char *p; + + if (s->full) + return 0; + + if (s->len >= (PAGE_SIZE - 1)) { + s->full = 1; + return 0; + } + + p = d_path(path, s->buffer + s->len, PAGE_SIZE - s->len); + if (!IS_ERR(p)) { + p = mangle_path(s->buffer + s->len, p, "\n"); + if (p) { + s->len = p - s->buffer; + return 1; + } + } else { + s->buffer[s->len++] = '?'; + return 1; + } + + s->full = 1; + return 0; +} + +ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) +{ + int len; + int ret; + + if (!cnt) + return 0; + + if (s->len <= s->readpos) + return -EBUSY; + + len = s->len - s->readpos; + if (cnt > len) + cnt = len; + ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); + if (ret == cnt) + return -EFAULT; + + cnt -= ret; + + s->readpos += cnt; + return cnt; +} -- cgit v1.2.3 From 36aabfff50b6a03bcfd2c3cfbd7b83eb0a9ce0c1 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 20 Jun 2014 17:38:01 -0400 Subject: tracing: Clean up trace_seq.c For using trace_seq_*() functions in NMI context, I posted a patch to move it to the lib/ directory. This caused Andrew Morton to take a look at the code. He went through and gave a lot of comments about missing kernel doc, inconsistent types for the save variable, mix match of EXPORT_SYMBOL_GPL() and EXPORT_SYMBOL() as well as missing EXPORT_SYMBOL*()s. There were a few comments about the way variables were being compared (int vs uint). All these were good review comments and should be implemented regardless of if trace_seq.c should be moved to lib/ or not. Signed-off-by: Steven Rostedt --- kernel/trace/trace_seq.c | 207 +++++++++++++++++++++++++++++++++++++++-------- 1 file changed, 175 insertions(+), 32 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 5ba99c6cf834..0fabca773e51 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -3,21 +3,55 @@ * * Copyright (C) 2008-2014 Red Hat Inc, Steven Rostedt * + * The trace_seq is a handy tool that allows you to pass a descriptor around + * to a buffer that other functions can write to. It is similar to the + * seq_file functionality but has some differences. + * + * To use it, the trace_seq must be initialized with trace_seq_init(). + * This will set up the counters within the descriptor. You can call + * trace_seq_init() more than once to reset the trace_seq to start + * from scratch. + * + * The buffer size is currently PAGE_SIZE, although it may become dynamic + * in the future. + * + * A write to the buffer will either succed or fail. That is, unlike + * sprintf() there will not be a partial write (well it may write into + * the buffer but it wont update the pointers). This allows users to + * try to write something into the trace_seq buffer and if it fails + * they can flush it and try again. + * */ #include #include #include +/* How much buffer is left on the trace_seq? */ +#define TRACE_SEQ_BUF_LEFT(s) ((PAGE_SIZE - 1) - (s)->len) + +/* How much buffer is written? */ +#define TRACE_SEQ_BUF_USED(s) min((s)->len, (unsigned int)(PAGE_SIZE - 1)) + +/** + * trace_print_seq - move the contents of trace_seq into a seq_file + * @m: the seq_file descriptor that is the destination + * @s: the trace_seq descriptor that is the source. + * + * Returns 0 on success and non zero on error. If it succeeds to + * write to the seq_file it will reset the trace_seq, otherwise + * it does not modify the trace_seq to let the caller try again. + */ int trace_print_seq(struct seq_file *m, struct trace_seq *s) { - int len = s->len >= PAGE_SIZE ? PAGE_SIZE - 1 : s->len; + unsigned int len = TRACE_SEQ_BUF_USED(s); int ret; ret = seq_write(m, s->buffer, len); /* * Only reset this buffer if we successfully wrote to the - * seq_file buffer. + * seq_file buffer. This lets the caller try again or + * do something else with the contents. */ if (!ret) trace_seq_init(s); @@ -30,19 +64,20 @@ int trace_print_seq(struct seq_file *m, struct trace_seq *s) * @s: trace sequence descriptor * @fmt: printf format string * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * * The tracer may use either sequence operations or its own * copy to user routines. To simplify formating of a trace - * trace_seq_printf is used to store strings into a special + * trace_seq_printf() is used to store strings into a special * buffer (@s). Then the output may be either used by * the sequencer or pulled into another buffer. + * + * Returns 1 if we successfully written all the contents to + * the buffer. + * Returns 0 if we the length to write is bigger than the + * reserved buffer space. In this case, nothing gets written. */ -int -trace_seq_printf(struct trace_seq *s, const char *fmt, ...) +int trace_seq_printf(struct trace_seq *s, const char *fmt, ...) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); va_list ap; int ret; @@ -66,21 +101,22 @@ trace_seq_printf(struct trace_seq *s, const char *fmt, ...) EXPORT_SYMBOL_GPL(trace_seq_printf); /** - * trace_seq_bitmask - put a list of longs as a bitmask print output + * trace_seq_bitmask - write a bitmask array in its ASCII representation * @s: trace sequence descriptor * @maskp: points to an array of unsigned longs that represent a bitmask * @nmaskbits: The number of bits that are valid in @maskp * - * It returns 0 if the trace oversizes the buffer's free - * space, 1 otherwise. - * * Writes a ASCII representation of a bitmask string into @s. + * + * Returns 1 if we successfully written all the contents to + * the buffer. + * Returns 0 if we the length to write is bigger than the + * reserved buffer space. In this case, nothing gets written. */ -int -trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, - int nmaskbits) +int trace_seq_bitmask(struct trace_seq *s, const unsigned long *maskp, + int nmaskbits) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); int ret; if (s->full || !len) @@ -103,11 +139,12 @@ EXPORT_SYMBOL_GPL(trace_seq_bitmask); * trace_seq_printf is used to store strings into a special * buffer (@s). Then the output may be either used by * the sequencer or pulled into another buffer. + * + * Returns how much it wrote to the buffer. */ -int -trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) +int trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); int ret; if (s->full || !len) @@ -127,9 +164,26 @@ trace_seq_vprintf(struct trace_seq *s, const char *fmt, va_list args) } EXPORT_SYMBOL_GPL(trace_seq_vprintf); +/** + * trace_seq_bprintf - Write the printf string from binary arguments + * @s: trace sequence descriptor + * @fmt: The format string for the @binary arguments + * @binary: The binary arguments for @fmt. + * + * When recording in a fast path, a printf may be recorded with just + * saving the format and the arguments as they were passed to the + * function, instead of wasting cycles converting the arguments into + * ASCII characters. Instead, the arguments are saved in a 32 bit + * word array that is defined by the format string constraints. + * + * This function will take the format and the binary array and finish + * the conversion into the ASCII string within the buffer. + * + * Returns how much it wrote to the buffer. + */ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) { - int len = (PAGE_SIZE - 1) - s->len; + unsigned int len = TRACE_SEQ_BUF_LEFT(s); int ret; if (s->full || !len) @@ -147,6 +201,7 @@ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) return len; } +EXPORT_SYMBOL_GPL(trace_seq_bprintf); /** * trace_seq_puts - trace sequence printing of simple string @@ -157,15 +212,17 @@ int trace_seq_bprintf(struct trace_seq *s, const char *fmt, const u32 *binary) * copy to user routines. This function records a simple string * into a special buffer (@s) for later retrieval by a sequencer * or other mechanism. + * + * Returns how much it wrote to the buffer. */ int trace_seq_puts(struct trace_seq *s, const char *str) { - int len = strlen(str); + unsigned int len = strlen(str); if (s->full) return 0; - if (len > ((PAGE_SIZE - 1) - s->len)) { + if (len > TRACE_SEQ_BUF_LEFT(s)) { s->full = 1; return 0; } @@ -175,13 +232,26 @@ int trace_seq_puts(struct trace_seq *s, const char *str) return len; } +EXPORT_SYMBOL_GPL(trace_seq_puts); +/** + * trace_seq_putc - trace sequence printing of simple character + * @s: trace sequence descriptor + * @c: simple character to record + * + * The tracer may use either the sequence operations or its own + * copy to user routines. This function records a simple charater + * into a special buffer (@s) for later retrieval by a sequencer + * or other mechanism. + * + * Returns how much it wrote to the buffer. + */ int trace_seq_putc(struct trace_seq *s, unsigned char c) { if (s->full) return 0; - if (s->len >= (PAGE_SIZE - 1)) { + if (TRACE_SEQ_BUF_LEFT(s) < 1) { s->full = 1; return 0; } @@ -190,14 +260,26 @@ int trace_seq_putc(struct trace_seq *s, unsigned char c) return 1; } -EXPORT_SYMBOL(trace_seq_putc); +EXPORT_SYMBOL_GPL(trace_seq_putc); -int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) +/** + * trace_seq_putmem - write raw data into the trace_seq buffer + * @s: trace sequence descriptor + * @mem: The raw memory to copy into the buffer + * @len: The length of the raw memory to copy (in bytes) + * + * There may be cases where raw memory needs to be written into the + * buffer and a strcpy() would not work. Using this function allows + * for such cases. + * + * Returns how much it wrote to the buffer. + */ +int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) { if (s->full) return 0; - if (len > ((PAGE_SIZE - 1) - s->len)) { + if (len > TRACE_SEQ_BUF_LEFT(s)) { s->full = 1; return 0; } @@ -207,10 +289,24 @@ int trace_seq_putmem(struct trace_seq *s, const void *mem, size_t len) return len; } +EXPORT_SYMBOL_GPL(trace_seq_putmem); #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) -int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) +/** + * trace_seq_putmem_hex - write raw memory into the buffer in ASCII hex + * @s: trace sequence descriptor + * @mem: The raw memory to write its hex ASCII representation of + * @len: The length of the raw memory to copy (in bytes) + * + * This is similar to trace_seq_putmem() except instead of just copying the + * raw memory into the buffer it writes its ASCII representation of it + * in hex characters. + * + * Returns how much it wrote to the buffer. + */ +int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, + unsigned int len) { unsigned char hex[HEX_CHARS]; const unsigned char *data = mem; @@ -231,15 +327,27 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, size_t len) return trace_seq_putmem(s, hex, j); } +EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); -void *trace_seq_reserve(struct trace_seq *s, size_t len) +/** + * trace_seq_reserve - reserve space on the sequence buffer + * @s: trace sequence descriptor + * @len: The amount to reserver. + * + * If for some reason there is a need to save some space on the + * buffer to fill in later, this function is used for that purpose. + * The given length will be reserved and the pointer to that + * location on the buffer is returned, unless there is not enough + * buffer left to hold the given length then NULL is returned. + */ +void *trace_seq_reserve(struct trace_seq *s, unsigned int len) { void *ret; if (s->full) return NULL; - if (len > ((PAGE_SIZE - 1) - s->len)) { + if (len > TRACE_SEQ_BUF_LEFT(s)) { s->full = 1; return NULL; } @@ -249,7 +357,20 @@ void *trace_seq_reserve(struct trace_seq *s, size_t len) return ret; } +EXPORT_SYMBOL_GPL(trace_seq_reserve); +/** + * trace_seq_path - copy a path into the sequence buffer + * @s: trace sequence descriptor + * @path: path to write into the sequence buffer. + * + * Write a path name into the sequence buffer. + * + * Returns 1 if we successfully written all the contents to + * the buffer. + * Returns 0 if we the length to write is bigger than the + * reserved buffer space. In this case, nothing gets written. + */ int trace_seq_path(struct trace_seq *s, const struct path *path) { unsigned char *p; @@ -257,7 +378,7 @@ int trace_seq_path(struct trace_seq *s, const struct path *path) if (s->full) return 0; - if (s->len >= (PAGE_SIZE - 1)) { + if (TRACE_SEQ_BUF_LEFT(s) < 1) { s->full = 1; return 0; } @@ -277,8 +398,29 @@ int trace_seq_path(struct trace_seq *s, const struct path *path) s->full = 1; return 0; } +EXPORT_SYMBOL_GPL(trace_seq_path); -ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) +/** + * trace_seq_to_user - copy the squence buffer to user space + * @s: trace sequence descriptor + * @ubuf: The userspace memory location to copy to + * @cnt: The amount to copy + * + * Copies the sequence buffer into the userspace memory pointed to + * by @ubuf. It starts from the last read position (@s->readpos) + * and writes up to @cnt characters or till it reaches the end of + * the content in the buffer (@s->len), which ever comes first. + * + * On success, it returns a positive number of the number of bytes + * it copied. + * + * On failure it returns -EBUSY if all of the content in the + * sequence has been already read, which includes nothing in the + * sequenc (@s->len == @s->readpos). + * + * Returns -EFAULT if the copy to userspace fails. + */ +int trace_seq_to_user(struct trace_seq *s, char __user *ubuf, int cnt) { int len; int ret; @@ -301,3 +443,4 @@ ssize_t trace_seq_to_user(struct trace_seq *s, char __user *ubuf, size_t cnt) s->readpos += cnt; return cnt; } +EXPORT_SYMBOL_GPL(trace_seq_to_user); -- cgit v1.2.3 From 6d2289f3faa71dcc5bba15c7aeba4f31c185b6df Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 20 Jun 2014 23:31:26 -0400 Subject: tracing: Make trace_seq_putmem_hex() more robust Currently trace_seq_putmem_hex() can only take as a parameter a pointer to something that is 8 bytes or less, otherwise it will overflow the buffer. This is protected by a macro that encompasses the call to trace_seq_putmem_hex() that has a BUILD_BUG_ON() for the variable before it is passed in. This is not very robust and if trace_seq_putmem_hex() ever gets used outside that macro it will cause issues. Instead of only being able to produce a hex output of memory that is for a single word, change it to be more robust and allow any size input. Signed-off-by: Steven Rostedt --- kernel/trace/trace_output.h | 1 - kernel/trace/trace_seq.c | 26 +++++++++++++++++++------- 2 files changed, 19 insertions(+), 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_output.h b/kernel/trace/trace_output.h index bf7daf2237ed..80b25b585a70 100644 --- a/kernel/trace/trace_output.h +++ b/kernel/trace/trace_output.h @@ -43,7 +43,6 @@ do { \ #define SEQ_PUT_HEX_FIELD_RET(s, x) \ do { \ - BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES); \ if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \ return TRACE_TYPE_PARTIAL_LINE; \ } while (0) diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 0fabca773e51..88c0f80f0a1f 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -291,6 +291,7 @@ int trace_seq_putmem(struct trace_seq *s, const void *mem, unsigned int len) } EXPORT_SYMBOL_GPL(trace_seq_putmem); +#define MAX_MEMHEX_BYTES 8U #define HEX_CHARS (MAX_MEMHEX_BYTES*2 + 1) /** @@ -310,22 +311,33 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, { unsigned char hex[HEX_CHARS]; const unsigned char *data = mem; + unsigned int start_len; int i, j; + int cnt = 0; if (s->full) return 0; + while (len) { + start_len = min(len, HEX_CHARS - 1); #ifdef __BIG_ENDIAN - for (i = 0, j = 0; i < len; i++) { + for (i = 0, j = 0; i < start_len; i++) { #else - for (i = len-1, j = 0; i >= 0; i--) { + for (i = start_len-1, j = 0; i >= 0; i--) { #endif - hex[j++] = hex_asc_hi(data[i]); - hex[j++] = hex_asc_lo(data[i]); - } - hex[j++] = ' '; + hex[j++] = hex_asc_hi(data[i]); + hex[j++] = hex_asc_lo(data[i]); + } + if (WARN_ON_ONCE(j == 0 || j/2 > len)) + break; + + /* j increments twice per loop */ + len -= j / 2; + hex[j++] = ' '; - return trace_seq_putmem(s, hex, j); + cnt += trace_seq_putmem(s, hex, j); + } + return cnt; } EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); -- cgit v1.2.3 From 9096032fbcdcdb80b76f1046346499e20417988e Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Mon, 23 Jun 2014 16:42:07 -0400 Subject: tracing: Remove trace_seq_reserve() trace_seq_reserve() has no users in the kernel, it just wastes space. Remove it. Cc: Eduard - Gabriel Munteanu Signed-off-by: Steven Rostedt --- kernel/trace/trace_seq.c | 30 ------------------------------ 1 file changed, 30 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_seq.c b/kernel/trace/trace_seq.c index 88c0f80f0a1f..1f24ed99dca2 100644 --- a/kernel/trace/trace_seq.c +++ b/kernel/trace/trace_seq.c @@ -341,36 +341,6 @@ int trace_seq_putmem_hex(struct trace_seq *s, const void *mem, } EXPORT_SYMBOL_GPL(trace_seq_putmem_hex); -/** - * trace_seq_reserve - reserve space on the sequence buffer - * @s: trace sequence descriptor - * @len: The amount to reserver. - * - * If for some reason there is a need to save some space on the - * buffer to fill in later, this function is used for that purpose. - * The given length will be reserved and the pointer to that - * location on the buffer is returned, unless there is not enough - * buffer left to hold the given length then NULL is returned. - */ -void *trace_seq_reserve(struct trace_seq *s, unsigned int len) -{ - void *ret; - - if (s->full) - return NULL; - - if (len > TRACE_SEQ_BUF_LEFT(s)) { - s->full = 1; - return NULL; - } - - ret = s->buffer + s->len; - s->len += len; - - return ret; -} -EXPORT_SYMBOL_GPL(trace_seq_reserve); - /** * trace_seq_path - copy a path into the sequence buffer * @s: trace sequence descriptor -- cgit v1.2.3 From 3f4d8f78a07dba1cb333ce749bd6a15c1ada362d Mon Sep 17 00:00:00 2001 From: Fabian Frederick Date: Thu, 26 Jun 2014 19:14:31 +0200 Subject: tracing: Remove unnecessary null test before debugfs_remove() This fixes checkpatch warning: "WARNING: debugfs_remove(NULL) is safe this check is probably not required" Link: http://lkml.kernel.org/p/1403802871-8599-1-git-send-email-fabf@skynet.be Signed-off-by: Fabian Frederick Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index eeb233cbac4f..4caa814d41c3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6071,10 +6071,8 @@ destroy_trace_option_files(struct trace_option_dentry *topts) if (!topts) return; - for (cnt = 0; topts[cnt].opt; cnt++) { - if (topts[cnt].entry) - debugfs_remove(topts[cnt].entry); - } + for (cnt = 0; topts[cnt].opt; cnt++) + debugfs_remove(topts[cnt].entry); kfree(topts); } -- cgit v1.2.3 From 7b039cb4c5a90d8ea576b17e096f7334457aeb57 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 26 Jun 2014 09:42:41 -0400 Subject: tracing: Add trace_seq_buffer_ptr() helper function There's several locations in the kernel that open code the calculation of the next location in the trace_seq buffer. This is usually done with p->buffer + p->len Instead of having this open coded, supply a helper function in the header to do it for them. This function is called trace_seq_buffer_ptr(). Link: http://lkml.kernel.org/p/20140626220129.452783019@goodmis.org Acked-by: Paolo Bonzini Signed-off-by: Steven Rostedt --- kernel/trace/trace_output.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index b8930f79a04b..c6977d5a9b12 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -75,7 +75,7 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim, { unsigned long mask; const char *str; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); int i, first = 1; for (i = 0; flag_array[i].name && flags; i++) { @@ -111,7 +111,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, const struct trace_print_flags *symbol_array) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; symbol_array[i].name; i++) { @@ -122,7 +122,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val, break; } - if (ret == (const char *)(p->buffer + p->len)) + if (ret == (const char *)(trace_seq_buffer_ptr(p))) trace_seq_printf(p, "0x%lx", val); trace_seq_putc(p, 0); @@ -137,7 +137,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, const struct trace_print_flags_u64 *symbol_array) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; symbol_array[i].name; i++) { @@ -148,7 +148,7 @@ ftrace_print_symbols_seq_u64(struct trace_seq *p, unsigned long long val, break; } - if (ret == (const char *)(p->buffer + p->len)) + if (ret == (const char *)(trace_seq_buffer_ptr(p))) trace_seq_printf(p, "0x%llx", val); trace_seq_putc(p, 0); @@ -162,7 +162,7 @@ const char * ftrace_print_bitmask_seq(struct trace_seq *p, void *bitmask_ptr, unsigned int bitmask_size) { - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); trace_seq_bitmask(p, bitmask_ptr, bitmask_size * 8); trace_seq_putc(p, 0); @@ -175,7 +175,7 @@ const char * ftrace_print_hex_seq(struct trace_seq *p, const unsigned char *buf, int buf_len) { int i; - const char *ret = p->buffer + p->len; + const char *ret = trace_seq_buffer_ptr(p); for (i = 0; i < buf_len; i++) trace_seq_printf(p, "%s%2.2x", i == 0 ? "" : " ", buf[i]); -- cgit v1.2.3 From a737e6dd7bfbd6d87ce1525840e6957bcb6e47e6 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Thu, 12 Jun 2014 23:56:12 +0900 Subject: ftrace: Get rid of obsolete global_start_up variable It seems like it's a leftover from commit 4104d326b670 ("ftrace: Remove global function list and call function directly"). As it isn't updated at all, checking its value is meaningless. Let's get rid of it. Link: http://lkml.kernel.org/p/1402584972-17824-1-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 8323082dbc21..39df3192e725 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2286,7 +2286,6 @@ static void ftrace_run_update_code(int command) static ftrace_func_t saved_ftrace_func; static int ftrace_start_up; -static int global_start_up; static void control_ops_free(struct ftrace_ops *ops) { @@ -2350,8 +2349,7 @@ static int ftrace_shutdown(struct ftrace_ops *ops, int command) ftrace_hash_rec_disable(ops, 1); - if (!global_start_up) - ops->flags &= ~FTRACE_OPS_FL_ENABLED; + ops->flags &= ~FTRACE_OPS_FL_ENABLED; command |= FTRACE_UPDATE_CALLS; -- cgit v1.2.3 From 1f61be007e16a5d60b1cf868aa30d87f181e8e14 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Wed, 11 Jun 2014 17:06:53 +0900 Subject: ftrace: Fix memory leak on failure path in ftrace_allocate_pages() As struct ftrace_page is managed in a single linked list, it should free from the start page. Link: http://lkml.kernel.org/p/1402474014-28655-1-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 39df3192e725..e14ff4c1713e 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2637,7 +2637,8 @@ ftrace_allocate_pages(unsigned long num_to_init) return start_pg; free_pages: - while (start_pg) { + pg = start_pg; + while (pg) { order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); start_pg = pg->next; -- cgit v1.2.3 From ef2fbe16ac176c21e3b3013c169e6fdb71ec56c7 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Wed, 11 Jun 2014 17:06:54 +0900 Subject: ftrace: Do not copy hash if O_TRUNC is set When a filter file is open for writing and O_TRUNC is set, there's no need to copy and free the filter entries. Link: http://lkml.kernel.org/p/1402474014-28655-2-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index e14ff4c1713e..232b898eebbd 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3010,7 +3010,13 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, hash = ops->filter_hash; if (file->f_mode & FMODE_WRITE) { - iter->hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, hash); + const int size_bits = FTRACE_HASH_DEFAULT_BITS; + + if (file->f_flags & O_TRUNC) + iter->hash = alloc_ftrace_hash(size_bits); + else + iter->hash = alloc_and_copy_ftrace_hash(size_bits, hash); + if (!iter->hash) { trace_parser_put(&iter->parser); kfree(iter); @@ -3019,10 +3025,6 @@ ftrace_regex_open(struct ftrace_ops *ops, int flag, } } - if ((file->f_mode & FMODE_WRITE) && - (file->f_flags & O_TRUNC)) - ftrace_filter_reset(iter->hash); - if (file->f_mode & FMODE_READ) { iter->pg = ftrace_pages_start; -- cgit v1.2.3 From 3448bac32953f051be91cef6d67025869f08dc4d Mon Sep 17 00:00:00 2001 From: Fabian Frederick Date: Sat, 7 Jun 2014 13:43:08 +0200 Subject: tracing: Convert pr_warning() to pr_warn() in trace_events.c Convert pr_warning to standard pr_warn Define pr_fmt(fmt) fmt to avoid any future default fmt definition Link: http://lkml.kernel.org/p/1402141388-21144-1-git-send-email-fabf@skynet.be Signed-off-by: Fabian Frederick Signed-off-by: Steven Rostedt --- kernel/trace/trace_events.c | 56 ++++++++++++++++++++++----------------------- 1 file changed, 27 insertions(+), 29 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index f99e0b3bca8c..e7a814b3906b 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -8,6 +8,8 @@ * */ +#define pr_fmt(fmt) fmt + #include #include #include @@ -1490,7 +1492,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name, dir->entry = debugfs_create_dir(name, parent); if (!dir->entry) { - pr_warning("Failed to create system directory %s\n", name); + pr_warn("Failed to create system directory %s\n", name); __put_system(system); goto out_free; } @@ -1506,7 +1508,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name, if (!entry) { kfree(system->filter); system->filter = NULL; - pr_warning("Could not create debugfs '%s/filter' entry\n", name); + pr_warn("Could not create debugfs '%s/filter' entry\n", name); } trace_create_file("enable", 0644, dir->entry, dir, @@ -1521,8 +1523,7 @@ event_subsystem_dir(struct trace_array *tr, const char *name, out_fail: /* Only print this message if failed on memory allocation */ if (!dir || !system) - pr_warning("No memory to create event subsystem %s\n", - name); + pr_warn("No memory to create event subsystem %s\n", name); return NULL; } @@ -1550,8 +1551,7 @@ event_create_dir(struct dentry *parent, struct ftrace_event_file *file) name = ftrace_event_name(call); file->dir = debugfs_create_dir(name, d_events); if (!file->dir) { - pr_warning("Could not create debugfs '%s' directory\n", - name); + pr_warn("Could not create debugfs '%s' directory\n", name); return -1; } @@ -1574,8 +1574,8 @@ event_create_dir(struct dentry *parent, struct ftrace_event_file *file) if (list_empty(head)) { ret = call->class->define_fields(call); if (ret < 0) { - pr_warning("Could not initialize trace point" - " events/%s\n", name); + pr_warn("Could not initialize trace point events/%s\n", + name); return -1; } } @@ -1648,8 +1648,7 @@ static int event_init(struct ftrace_event_call *call) if (call->class->raw_init) { ret = call->class->raw_init(call); if (ret < 0 && ret != -ENOSYS) - pr_warn("Could not initialize trace events/%s\n", - name); + pr_warn("Could not initialize trace events/%s\n", name); } return ret; @@ -1894,8 +1893,8 @@ __trace_add_event_dirs(struct trace_array *tr) list_for_each_entry(call, &ftrace_events, list) { ret = __trace_add_new_event(call, tr); if (ret < 0) - pr_warning("Could not create directory for event %s\n", - ftrace_event_name(call)); + pr_warn("Could not create directory for event %s\n", + ftrace_event_name(call)); } } @@ -2207,8 +2206,8 @@ __trace_early_add_event_dirs(struct trace_array *tr) list_for_each_entry(file, &tr->events, list) { ret = event_create_dir(tr->event_dir, file); if (ret < 0) - pr_warning("Could not create directory for event %s\n", - ftrace_event_name(file->event_call)); + pr_warn("Could not create directory for event %s\n", + ftrace_event_name(file->event_call)); } } @@ -2231,8 +2230,8 @@ __trace_early_add_events(struct trace_array *tr) ret = __trace_early_add_new_event(call, tr); if (ret < 0) - pr_warning("Could not create early event %s\n", - ftrace_event_name(call)); + pr_warn("Could not create early event %s\n", + ftrace_event_name(call)); } } @@ -2279,13 +2278,13 @@ create_event_toplevel_files(struct dentry *parent, struct trace_array *tr) entry = debugfs_create_file("set_event", 0644, parent, tr, &ftrace_set_event_fops); if (!entry) { - pr_warning("Could not create debugfs 'set_event' entry\n"); + pr_warn("Could not create debugfs 'set_event' entry\n"); return -ENOMEM; } d_events = debugfs_create_dir("events", parent); if (!d_events) { - pr_warning("Could not create debugfs 'events' directory\n"); + pr_warn("Could not create debugfs 'events' directory\n"); return -ENOMEM; } @@ -2461,11 +2460,10 @@ static __init int event_trace_init(void) entry = debugfs_create_file("available_events", 0444, d_tracer, tr, &ftrace_avail_fops); if (!entry) - pr_warning("Could not create debugfs " - "'available_events' entry\n"); + pr_warn("Could not create debugfs 'available_events' entry\n"); if (trace_define_common_fields()) - pr_warning("tracing: Failed to allocate common fields"); + pr_warn("tracing: Failed to allocate common fields"); ret = early_event_add_tracer(d_tracer, tr); if (ret) @@ -2474,7 +2472,7 @@ static __init int event_trace_init(void) #ifdef CONFIG_MODULES ret = register_module_notifier(&trace_module_nb); if (ret) - pr_warning("Failed to register trace events module notifier\n"); + pr_warn("Failed to register trace events module notifier\n"); #endif return 0; } @@ -2578,7 +2576,7 @@ static __init void event_trace_self_tests(void) * it and the self test should not be on. */ if (file->flags & FTRACE_EVENT_FL_ENABLED) { - pr_warning("Enabled event during self test!\n"); + pr_warn("Enabled event during self test!\n"); WARN_ON_ONCE(1); continue; } @@ -2606,8 +2604,8 @@ static __init void event_trace_self_tests(void) ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 1); if (WARN_ON_ONCE(ret)) { - pr_warning("error enabling system %s\n", - system->name); + pr_warn("error enabling system %s\n", + system->name); continue; } @@ -2615,8 +2613,8 @@ static __init void event_trace_self_tests(void) ret = __ftrace_set_clr_event(tr, NULL, system->name, NULL, 0); if (WARN_ON_ONCE(ret)) { - pr_warning("error disabling system %s\n", - system->name); + pr_warn("error disabling system %s\n", + system->name); continue; } @@ -2630,7 +2628,7 @@ static __init void event_trace_self_tests(void) ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 1); if (WARN_ON_ONCE(ret)) { - pr_warning("error enabling all events\n"); + pr_warn("error enabling all events\n"); return; } @@ -2639,7 +2637,7 @@ static __init void event_trace_self_tests(void) /* reset sysname */ ret = __ftrace_set_clr_event(tr, NULL, NULL, NULL, 0); if (WARN_ON_ONCE(ret)) { - pr_warning("error disabling all events\n"); + pr_warn("error disabling all events\n"); return; } -- cgit v1.2.3 From 0d7d9a16ce112687487fadb2b490519b45f6c70e Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 13 Jun 2014 01:23:50 +0900 Subject: tracing: Add ftrace_graph_notrace boot parameter The ftrace_graph_notrace option is for specifying notrace filter for function graph tracer at boot time. It can be altered after boot using set_graph_notrace file on the debugfs. Link: http://lkml.kernel.org/p/1402590233-22321-2-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 232b898eebbd..17885a27281c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3884,6 +3884,7 @@ __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; +static char ftrace_graph_notrace_buf[FTRACE_FILTER_SIZE] __initdata; static int ftrace_set_func(unsigned long *array, int *idx, int size, char *buffer); static int __init set_graph_function(char *str) @@ -3893,16 +3894,29 @@ static int __init set_graph_function(char *str) } __setup("ftrace_graph_filter=", set_graph_function); -static void __init set_ftrace_early_graph(char *buf) +static int __init set_graph_notrace_function(char *str) +{ + strlcpy(ftrace_graph_notrace_buf, str, FTRACE_FILTER_SIZE); + return 1; +} +__setup("ftrace_graph_notrace=", set_graph_notrace_function); + +static void __init set_ftrace_early_graph(char *buf, int enable) { int ret; char *func; + unsigned long *table = ftrace_graph_funcs; + int *count = &ftrace_graph_count; + + if (!enable) { + table = ftrace_graph_notrace_funcs; + count = &ftrace_graph_notrace_count; + } while (buf) { func = strsep(&buf, ","); /* we allow only one expression at a time */ - ret = ftrace_set_func(ftrace_graph_funcs, &ftrace_graph_count, - FTRACE_GRAPH_MAX_FUNCS, func); + ret = ftrace_set_func(table, count, FTRACE_GRAPH_MAX_FUNCS, func); if (ret) printk(KERN_DEBUG "ftrace: function %s not " "traceable\n", func); @@ -3931,7 +3945,9 @@ static void __init set_ftrace_early_filters(void) ftrace_set_early_filter(&global_ops, ftrace_notrace_buf, 0); #ifdef CONFIG_FUNCTION_GRAPH_TRACER if (ftrace_graph_buf[0]) - set_ftrace_early_graph(ftrace_graph_buf); + set_ftrace_early_graph(ftrace_graph_buf, 1); + if (ftrace_graph_notrace_buf[0]) + set_ftrace_early_graph(ftrace_graph_notrace_buf, 0); #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ } -- cgit v1.2.3 From 280d1429b6a67432ead24fb68a504b4c90c3d96d Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 13 Jun 2014 01:23:51 +0900 Subject: tracing: Improve message of empty set_graph_notrace file When there's no entry in set_graph_notrace, it'll print below message #### all functions enabled #### While this is technically correct, it's better to print like below: #### no functions disabled #### Link: http://lkml.kernel.org/p/1402590233-22321-3-git-send-email-namhyung@kernel.org Reported-by: Naoya Horiguchi Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 17885a27281c..ee245c0659a6 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4089,7 +4089,12 @@ static int g_show(struct seq_file *m, void *v) return 0; if (ptr == (unsigned long *)1) { - seq_printf(m, "#### all functions enabled ####\n"); + struct ftrace_graph_data *fgd = m->private; + + if (fgd->table == ftrace_graph_funcs) + seq_printf(m, "#### all functions enabled ####\n"); + else + seq_printf(m, "#### no functions disabled ####\n"); return 0; } -- cgit v1.2.3 From 8c006cf7a2130c4bfb600ae3a496910115804641 Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 13 Jun 2014 16:24:06 +0900 Subject: tracing: Improve message of empty set_ftrace_notrace file When there's no entry in set_ftrace_notrace, it'll print nothing, but it's better to print something like below like set_graph_notrace does: #### no functions disabled #### Link: http://lkml.kernel.org/p/1402644246-4649-1-git-send-email-namhyung@kernel.org Reported-by: Naoya Horiguchi Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index ee245c0659a6..45aac1a742c5 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2835,8 +2835,10 @@ static void *t_start(struct seq_file *m, loff_t *pos) * off, we can short cut and just print out that all * functions are enabled. */ - if (iter->flags & FTRACE_ITER_FILTER && - ftrace_hash_empty(ops->filter_hash)) { + if ((iter->flags & FTRACE_ITER_FILTER && + ftrace_hash_empty(ops->filter_hash)) || + (iter->flags & FTRACE_ITER_NOTRACE && + ftrace_hash_empty(ops->notrace_hash))) { if (*pos > 0) return t_hash_start(m, pos); iter->flags |= FTRACE_ITER_PRINTALL; @@ -2881,7 +2883,10 @@ static int t_show(struct seq_file *m, void *v) return t_hash_show(m, iter); if (iter->flags & FTRACE_ITER_PRINTALL) { - seq_printf(m, "#### all functions enabled ####\n"); + if (iter->flags & FTRACE_ITER_NOTRACE) + seq_printf(m, "#### no functions disabled ####\n"); + else + seq_printf(m, "#### all functions enabled ####\n"); return 0; } -- cgit v1.2.3 From d048a8c7b509f35dd351e1415fe49fa99e4cb7ef Mon Sep 17 00:00:00 2001 From: Namhyung Kim Date: Fri, 13 Jun 2014 01:23:53 +0900 Subject: tracing: Add description of set_graph_notrace to tracing/README It was missing the description of set_graph_notrace file. Add it. Link: http://lkml.kernel.org/p/1402590233-22321-5-git-send-email-namhyung@kernel.org Signed-off-by: Namhyung Kim Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4caa814d41c3..822f6a0894f7 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3663,6 +3663,7 @@ static const char readme_msg[] = #endif #ifdef CONFIG_FUNCTION_GRAPH_TRACER " set_graph_function\t- Trace the nested calls of a function (function_graph)\n" + " set_graph_notrace\t- Do not trace the nested calls of a function (function_graph)\n" " max_graph_depth\t- Trace a limited depth of nested calls (0 is unlimited)\n" #endif #ifdef CONFIG_TRACER_SNAPSHOT -- cgit v1.2.3 From 646d7043adf3d92de5d3db1244a82a12628303de Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 11 Jul 2014 14:39:10 -0400 Subject: ftrace: Allow archs to specify if they need a separate function graph trampoline Currently if an arch supports function graph tracing, the core code will just assign the function graph trampoline to the function graph addr that gets called. But as the old method for function graph tracing always calls the function trampoline first and that calls the function graph trampoline, some archs may have the function graph trampoline dependent on operations that were done in the function trampoline. This causes function graph tracer to break on those archs. Instead of having the default be to set the function graph ftrace_ops to the function graph trampoline, have it instead just set it to zero which will keep it from jumping to a trampoline that is not set up to be jumped directly too. Link: http://lkml.kernel.org/r/53BED155.9040607@nvidia.com Reported-by: Tuomas Tynkkynen Tested-by: Tuomas Tynkkynen Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 45aac1a742c5..1776153ea6e0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5366,7 +5366,8 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc, #ifdef CONFIG_DYNAMIC_FTRACE /* Optimize function graph calling (if implemented by arch) */ - global_ops.trampoline = FTRACE_GRAPH_ADDR; + if (FTRACE_GRAPH_TRAMP_ADDR != 0) + global_ops.trampoline = FTRACE_GRAPH_TRAMP_ADDR; #endif ret = ftrace_startup(&global_ops, FTRACE_START_FUNC_RET); @@ -5390,7 +5391,8 @@ void unregister_ftrace_graph(void) ftrace_shutdown(&global_ops, FTRACE_STOP_FUNC_RET); global_ops.flags &= ~FTRACE_OPS_FL_STUB; #ifdef CONFIG_DYNAMIC_FTRACE - global_ops.trampoline = 0; + if (FTRACE_GRAPH_TRAMP_ADDR != 0) + global_ops.trampoline = 0; #endif unregister_pm_notifier(&ftrace_suspend_notifier); unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL); -- cgit v1.2.3 From 2b014666a1b93ad21c5667a4643da67bd49a5562 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Tue, 24 Jun 2014 23:38:08 -0400 Subject: PM / Sleep: Remove ftrace_stop/start() from suspend and hibernate ftrace_stop() and ftrace_start() were added to the suspend and hibernate process because there was some function within the work flow that caused the system to reboot if it was traced. This function has recently been found (restore_processor_state()). Now there's no reason to disable function tracing while we are going into suspend or hibernate, which means that being able to trace this will help tremendously in debugging any issues with suspend or hibernate. This also means that the ftrace_stop/start() functions can be removed and simplify the function tracing code a bit. Link: http://lkml.kernel.org/r/1518201.VD9cU33jRU@vostro.rjw.lan Acked-by: "Rafael J. Wysocki" Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/power/hibernate.c | 6 ------ kernel/power/suspend.c | 2 -- 2 files changed, 8 deletions(-) (limited to 'kernel') diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c index fcc2611d3f14..a9dfa79b6bab 100644 --- a/kernel/power/hibernate.c +++ b/kernel/power/hibernate.c @@ -371,7 +371,6 @@ int hibernation_snapshot(int platform_mode) } suspend_console(); - ftrace_stop(); pm_restrict_gfp_mask(); error = dpm_suspend(PMSG_FREEZE); @@ -397,7 +396,6 @@ int hibernation_snapshot(int platform_mode) if (error || !in_suspend) pm_restore_gfp_mask(); - ftrace_start(); resume_console(); dpm_complete(msg); @@ -500,7 +498,6 @@ int hibernation_restore(int platform_mode) pm_prepare_console(); suspend_console(); - ftrace_stop(); pm_restrict_gfp_mask(); error = dpm_suspend_start(PMSG_QUIESCE); if (!error) { @@ -508,7 +505,6 @@ int hibernation_restore(int platform_mode) dpm_resume_end(PMSG_RECOVER); } pm_restore_gfp_mask(); - ftrace_start(); resume_console(); pm_restore_console(); return error; @@ -535,7 +531,6 @@ int hibernation_platform_enter(void) entering_platform_hibernation = true; suspend_console(); - ftrace_stop(); error = dpm_suspend_start(PMSG_HIBERNATE); if (error) { if (hibernation_ops->recover) @@ -579,7 +574,6 @@ int hibernation_platform_enter(void) Resume_devices: entering_platform_hibernation = false; dpm_resume_end(PMSG_RESTORE); - ftrace_start(); resume_console(); Close: diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index 4dd8822f732a..f6623da034d8 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -248,7 +248,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) goto Platform_wake; } - ftrace_stop(); error = disable_nonboot_cpus(); if (error || suspend_test(TEST_CPUS)) goto Enable_cpus; @@ -275,7 +274,6 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) Enable_cpus: enable_nonboot_cpus(); - ftrace_start(); Platform_wake: if (need_suspend_ops(state) && suspend_ops->wake) -- cgit v1.2.3 From 1b2f121c1418249e56048d816754b479b3cb6fb3 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 10:39:46 -0400 Subject: ftrace-graph: Remove dependency of ftrace_stop() from ftrace_graph_stop() ftrace_stop() is going away as it disables parts of function tracing that affects users that should not be affected. But ftrace_graph_stop() is built on ftrace_stop(). Here's another example of killing all of function tracing because something went wrong with function graph tracing. Instead of disabling all users of function tracing on function graph error, disable only function graph tracing. A new function is created called ftrace_graph_is_dead(). This is called in strategic paths to prevent function graph from doing more harm and allowing at least a warning to be printed before the system crashes. NOTE: ftrace_stop() is still used until all the archs are converted over to use ftrace_graph_is_dead(). After that, ftrace_stop() will be removed. Reviewed-by: Masami Hiramatsu Cc: Frederic Weisbecker Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 5 ----- kernel/trace/trace_functions_graph.c | 35 +++++++++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 1776153ea6e0..8063280fd53d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5473,9 +5473,4 @@ void ftrace_graph_exit_task(struct task_struct *t) kfree(ret_stack); } - -void ftrace_graph_stop(void) -{ - ftrace_stop(); -} #endif diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 4de3e57f723c..3604690be70b 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -15,6 +15,38 @@ #include "trace.h" #include "trace_output.h" +static bool kill_ftrace_graph; + +/** + * ftrace_graph_is_dead - returns true if ftrace_graph_stop() was called + * + * ftrace_graph_stop() is called when a severe error is detected in + * the function graph tracing. This function is called by the critical + * paths of function graph to keep those paths from doing any more harm. + */ +bool ftrace_graph_is_dead(void) +{ + return kill_ftrace_graph; +} + +/** + * ftrace_graph_stop - set to permanently disable function graph tracincg + * + * In case of an error int function graph tracing, this is called + * to try to keep function graph tracing from causing any more harm. + * Usually this is pretty severe and this is called to try to at least + * get a warning out to the user. + */ +void ftrace_graph_stop(void) +{ + kill_ftrace_graph = true; + /* + * ftrace_stop() will be removed when all archs are updated to + * use ftrace_graph_is_dead() + */ + ftrace_stop(); +} + /* When set, irq functions will be ignored */ static int ftrace_graph_skip_irqs; @@ -92,6 +124,9 @@ ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth, unsigned long long calltime; int index; + if (unlikely(ftrace_graph_is_dead())) + return -EBUSY; + if (!current->ret_stack) return -EBUSY; -- cgit v1.2.3 From 545d47b8f359f7e9b5beabc28bfeecb3fc6af1ee Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 11:13:27 -0400 Subject: ftrace-graph: Remove usage of ftrace_stop() in ftrace_graph_stop() All archs now use ftrace_graph_is_dead() to stop function graph tracing. Remove the usage of ftrace_stop() as that is no longer needed. Cc: Frederic Weisbecker Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 3604690be70b..2c944e6c4a9d 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -40,11 +40,6 @@ bool ftrace_graph_is_dead(void) void ftrace_graph_stop(void) { kill_ftrace_graph = true; - /* - * ftrace_stop() will be removed when all archs are updated to - * use ftrace_graph_is_dead() - */ - ftrace_stop(); } /* When set, irq functions will be ignored */ -- cgit v1.2.3 From 1820122a76c6d64adc6e2a7ff438029ffb8d7cb4 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 11:28:20 -0400 Subject: ftrace: Do no disable function tracing on enabling function tracing When function tracing is being updated function_trace_stop is set to keep from tracing the updates. This was fine when function tracing was done from stop machine. But it is no longer done that way and this can cause real tracing to be missed. Remove it. Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 7 ------- 1 file changed, 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 8063280fd53d..0fa1b87db95c 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2261,11 +2261,6 @@ static void ftrace_run_update_code(int command) FTRACE_WARN_ON(ret); if (ret) return; - /* - * Do not call function tracer while we update the code. - * We are in stop machine. - */ - function_trace_stop++; /* * By default we use stop_machine() to modify the code. @@ -2275,8 +2270,6 @@ static void ftrace_run_update_code(int command) */ arch_ftrace_update_code(command); - function_trace_stop--; - ret = ftrace_arch_code_modify_post_process(); FTRACE_WARN_ON(ret); -- cgit v1.2.3 From 1d48d5960f9f24b8afd5b1dbb10bfe17b5f29a35 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 25 Jun 2014 11:54:03 -0400 Subject: ftrace: Remove function_trace_stop check from list func function_trace_stop is no longer used to stop function tracing. Remove the check from __ftrace_ops_list_func(). Also, call FTRACE_WARN_ON() instead of setting function_trace_stop if a ops has no func to call. Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0fa1b87db95c..70abf97d6e84 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4720,9 +4720,6 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *op; int bit; - if (function_trace_stop) - return; - bit = trace_test_and_set_recursion(TRACE_LIST_START, TRACE_LIST_MAX); if (bit < 0) return; @@ -4734,9 +4731,8 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip, preempt_disable_notrace(); do_for_each_ftrace_op(op, ftrace_ops_list) { if (ftrace_ops_test(op, ip, regs)) { - if (WARN_ON(!op->func)) { - function_trace_stop = 1; - printk("op=%p %pS\n", op, op); + if (FTRACE_WARN_ON(!op->func)) { + pr_warn("op=%p %pS\n", op, op); goto out; } op->func(ip, parent_ip, op, regs); -- cgit v1.2.3 From 3a636388bae8390d23f31e061c0c6fdc14525786 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 26 Jun 2014 11:24:52 -0400 Subject: tracing: Remove function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST All users of function_trace_stop and HAVE_FUNCTION_TRACE_MCOUNT_TEST have been removed. We can safely remove them from the kernel. Reviewed-by: Masami Hiramatsu Signed-off-by: Steven Rostedt --- kernel/trace/Kconfig | 5 ----- kernel/trace/ftrace.c | 3 --- 2 files changed, 8 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index d4409356f40d..a5da09c899dd 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -29,11 +29,6 @@ config HAVE_FUNCTION_GRAPH_FP_TEST help See Documentation/trace/ftrace-design.txt -config HAVE_FUNCTION_TRACE_MCOUNT_TEST - bool - help - See Documentation/trace/ftrace-design.txt - config HAVE_DYNAMIC_FTRACE bool help diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 70abf97d6e84..4c61f28a08e0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -80,9 +80,6 @@ static struct ftrace_ops ftrace_list_end __read_mostly = { int ftrace_enabled __read_mostly; static int last_ftrace_enabled; -/* Quick disabling of function tracer. */ -int function_trace_stop __read_mostly; - /* Current function tracing op */ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end; /* What to set function_trace_op to */ -- cgit v1.2.3 From 021c5b34452d52e51664f09b98cd50c5495e74b6 Mon Sep 17 00:00:00 2001 From: Corey Minyard Date: Wed, 16 Jul 2014 14:07:13 -0500 Subject: ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on() The code for resizing the trace ring buffers has to run the per-cpu resize on the CPU itself. The code was using preempt_off() and running the code for the current CPU directly, otherwise calling schedule_work_on(). At least on RT this could result in the following: |BUG: sleeping function called from invalid context at kernel/rtmutex.c:673 |in_atomic(): 1, irqs_disabled(): 0, pid: 607, name: bash |3 locks held by bash/607: |CPU: 0 PID: 607 Comm: bash Not tainted 3.12.15-rt25+ #124 |(rt_spin_lock+0x28/0x68) |(free_hot_cold_page+0x84/0x3b8) |(free_buffer_page+0x14/0x20) |(rb_update_pages+0x280/0x338) |(ring_buffer_resize+0x32c/0x3dc) |(free_snapshot+0x18/0x38) |(tracing_set_tracer+0x27c/0x2ac) probably via |cd /sys/kernel/debug/tracing/ |echo 1 > events/enable ; sleep 2 |echo 1024 > buffer_size_kb If we just always use schedule_work_on(), there's no need for the preempt_off(). So do that. Link: http://lkml.kernel.org/p/1405537633-31518-1-git-send-email-cminyard@mvista.com Reported-by: Stanislav Meduna Signed-off-by: Corey Minyard Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 24 ++++-------------------- 1 file changed, 4 insertions(+), 20 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 7c56c3d06943..35825a87d6a3 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1693,22 +1693,14 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, if (!cpu_buffer->nr_pages_to_update) continue; - /* The update must run on the CPU that is being updated. */ - preempt_disable(); - if (cpu == smp_processor_id() || !cpu_online(cpu)) { + /* Can't run something on an offline CPU. */ + if (!cpu_online(cpu)) { rb_update_pages(cpu_buffer); cpu_buffer->nr_pages_to_update = 0; } else { - /* - * Can not disable preemption for schedule_work_on() - * on PREEMPT_RT. - */ - preempt_enable(); schedule_work_on(cpu, &cpu_buffer->update_pages_work); - preempt_disable(); } - preempt_enable(); } /* wait for all the updates to complete */ @@ -1746,22 +1738,14 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size, get_online_cpus(); - preempt_disable(); - /* The update must run on the CPU that is being updated. */ - if (cpu_id == smp_processor_id() || !cpu_online(cpu_id)) + /* Can't run something on an offline CPU. */ + if (!cpu_online(cpu_id)) rb_update_pages(cpu_buffer); else { - /* - * Can not disable preemption for schedule_work_on() - * on PREEMPT_RT. - */ - preempt_enable(); schedule_work_on(cpu_id, &cpu_buffer->update_pages_work); wait_for_completion(&cpu_buffer->update_done); - preempt_disable(); } - preempt_enable(); cpu_buffer->nr_pages_to_update = 0; put_online_cpus(); -- cgit v1.2.3 From 6508fa761c330a1d2b4ae36199d08dbcb70e3ddb Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Fri, 18 Jul 2014 15:17:27 +0400 Subject: tracing: let user specify tracing_thresh after selecting function_graph Currently, tracing_thresh works only if we specify it before selecting function_graph tracer. If we do the opposite, tracing_thresh will change it's value, but it will not be applied. To fix it, we add update_thresh callback which is called whenever tracing_thresh is updated and for function_graph tracer we register handler which reinitializes tracer depending on tracing_thresh. Link: http://lkml.kernel.org/p/20140718111727.GA3206@stfomichev-desktop.yandex.net Signed-off-by: Stanislav Fomichev Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 65 ++++++++++++++++++++++++++++++++---- kernel/trace/trace.h | 2 ++ kernel/trace/trace_functions_graph.c | 7 ++++ 3 files changed, 67 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4a343db45d4e..2752147ed317 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4201,10 +4201,9 @@ tracing_set_trace_write(struct file *filp, const char __user *ubuf, } static ssize_t -tracing_max_lat_read(struct file *filp, char __user *ubuf, - size_t cnt, loff_t *ppos) +tracing_nsecs_read(unsigned long *ptr, char __user *ubuf, + size_t cnt, loff_t *ppos) { - unsigned long *ptr = filp->private_data; char buf[64]; int r; @@ -4216,10 +4215,9 @@ tracing_max_lat_read(struct file *filp, char __user *ubuf, } static ssize_t -tracing_max_lat_write(struct file *filp, const char __user *ubuf, - size_t cnt, loff_t *ppos) +tracing_nsecs_write(unsigned long *ptr, const char __user *ubuf, + size_t cnt, loff_t *ppos) { - unsigned long *ptr = filp->private_data; unsigned long val; int ret; @@ -4232,6 +4230,52 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf, return cnt; } +static ssize_t +tracing_thresh_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_read(&tracing_thresh, ubuf, cnt, ppos); +} + +static ssize_t +tracing_thresh_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + struct trace_array *tr = filp->private_data; + int ret; + + mutex_lock(&trace_types_lock); + ret = tracing_nsecs_write(&tracing_thresh, ubuf, cnt, ppos); + if (ret < 0) + goto out; + + if (tr->current_trace->update_thresh) { + ret = tr->current_trace->update_thresh(tr); + if (ret < 0) + goto out; + } + + ret = cnt; +out: + mutex_unlock(&trace_types_lock); + + return ret; +} + +static ssize_t +tracing_max_lat_read(struct file *filp, char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_read(filp->private_data, ubuf, cnt, ppos); +} + +static ssize_t +tracing_max_lat_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + return tracing_nsecs_write(filp->private_data, ubuf, cnt, ppos); +} + static int tracing_open_pipe(struct inode *inode, struct file *filp) { struct trace_array *tr = inode->i_private; @@ -5133,6 +5177,13 @@ static int snapshot_raw_open(struct inode *inode, struct file *filp) #endif /* CONFIG_TRACER_SNAPSHOT */ +static const struct file_operations tracing_thresh_fops = { + .open = tracing_open_generic, + .read = tracing_thresh_read, + .write = tracing_thresh_write, + .llseek = generic_file_llseek, +}; + static const struct file_operations tracing_max_lat_fops = { .open = tracing_open_generic, .read = tracing_max_lat_read, @@ -6494,7 +6545,7 @@ static __init int tracer_init_debugfs(void) init_tracer_debugfs(&global_trace, d_tracer); trace_create_file("tracing_thresh", 0644, d_tracer, - &tracing_thresh, &tracing_max_lat_fops); + &global_trace, &tracing_thresh_fops); trace_create_file("README", 0444, d_tracer, NULL, &tracing_readme_fops); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 9258f5a815db..385391fb1d3b 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -339,6 +339,7 @@ struct tracer_flags { * @reset: called when one switches to another tracer * @start: called when tracing is unpaused (echo 1 > tracing_enabled) * @stop: called when tracing is paused (echo 0 > tracing_enabled) + * @update_thresh: called when tracing_thresh is updated * @open: called when the trace file is opened * @pipe_open: called when the trace_pipe file is opened * @close: called when the trace file is released @@ -357,6 +358,7 @@ struct tracer { void (*reset)(struct trace_array *tr); void (*start)(struct trace_array *tr); void (*stop)(struct trace_array *tr); + int (*update_thresh)(struct trace_array *tr); void (*open)(struct trace_iterator *iter); void (*pipe_open)(struct trace_iterator *iter); void (*close)(struct trace_iterator *iter); diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 2c944e6c4a9d..74d98820497c 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -475,6 +475,12 @@ static void graph_trace_reset(struct trace_array *tr) unregister_ftrace_graph(); } +int graph_trace_update_thresh(struct trace_array *tr) +{ + graph_trace_reset(tr); + return graph_trace_init(tr); +} + static int max_bytes_for_cpu; static enum print_line_t @@ -1525,6 +1531,7 @@ static struct trace_event graph_trace_ret_event = { static struct tracer graph_trace __tracer_data = { .name = "function_graph", + .update_thresh = graph_trace_update_thresh, .open = graph_trace_open, .pipe_open = graph_trace_open, .close = graph_trace_close, -- cgit v1.2.3 From b972cc58ced01ba2cf1f67b36bcfbb3ed4fa706e Mon Sep 17 00:00:00 2001 From: Wang Nan Date: Tue, 15 Jul 2014 08:40:20 +0800 Subject: ftrace: Do not copy old hash when resetting Do not waste time copying the old hash if the hash is going to be reset. Just allocate a new hash and free the old one, as that is the same result as copying te old one and then resetting it. Link: http://lkml.kernel.org/p/1405384820-48837-1-git-send-email-wangnan0@huawei.com Signed-off-by: Wang Nan [ SDR: Removed unused ftrace_filter_reset() function ] Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 15 +++++---------- 1 file changed, 5 insertions(+), 10 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 4c61f28a08e0..762806026561 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2949,13 +2949,6 @@ ftrace_enabled_open(struct inode *inode, struct file *file) return iter ? 0 : -ENOMEM; } -static void ftrace_filter_reset(struct ftrace_hash *hash) -{ - mutex_lock(&ftrace_lock); - ftrace_hash_clear(hash); - mutex_unlock(&ftrace_lock); -} - /** * ftrace_regex_open - initialize function tracer filter files * @ops: The ftrace_ops that hold the hash filters @@ -3720,14 +3713,16 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len, else orig_hash = &ops->notrace_hash; - hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); + if (reset) + hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS); + else + hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash); + if (!hash) { ret = -ENOMEM; goto out_regex_unlock; } - if (reset) - ftrace_filter_reset(hash); if (buf && !ftrace_match_records(hash, buf, len)) { ret = -EINVAL; goto out_regex_unlock; -- cgit v1.2.3 From ba1afef6a47c4133831fefcad4e0d7bf1d0ee99e Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Fri, 18 Jul 2014 18:07:49 -0400 Subject: tracing: Convert local function_graph functions to static Local functions should be static. Reported-by: kbuild test robot Signed-off-by: Steven Rostedt --- kernel/trace/trace_functions_graph.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c index 74d98820497c..f0a0c982cde3 100644 --- a/kernel/trace/trace_functions_graph.c +++ b/kernel/trace/trace_functions_graph.c @@ -353,7 +353,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace) return ret; } -int trace_graph_thresh_entry(struct ftrace_graph_ent *trace) +static int trace_graph_thresh_entry(struct ftrace_graph_ent *trace) { if (tracing_thresh) return 1; @@ -442,7 +442,7 @@ void set_graph_array(struct trace_array *tr) smp_mb(); } -void trace_graph_thresh_return(struct ftrace_graph_ret *trace) +static void trace_graph_thresh_return(struct ftrace_graph_ret *trace) { if (tracing_thresh && (trace->rettime - trace->calltime < tracing_thresh)) @@ -475,7 +475,7 @@ static void graph_trace_reset(struct trace_array *tr) unregister_ftrace_graph(); } -int graph_trace_update_thresh(struct trace_array *tr) +static int graph_trace_update_thresh(struct trace_array *tr) { graph_trace_reset(tr); return graph_trace_init(tr); @@ -1435,7 +1435,7 @@ static void __print_graph_headers_flags(struct seq_file *s, u32 flags) seq_printf(s, " | | | |\n"); } -void print_graph_headers(struct seq_file *s) +static void print_graph_headers(struct seq_file *s) { print_graph_headers_flags(s, tracer_flags.val); } -- cgit v1.2.3 From 0162d621ddf3bd02bf7de324dcf002d9c84c5059 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 23 Jul 2014 15:03:00 -0400 Subject: ftrace: Rename ftrace_ops field from trampolines to nr_trampolines Having two fields within the same struct that is off by one character can be confusing and error prone. Rename the counter "trampolines" to "nr_trampolines" to explicitly show it is a counter and not to be confused by the "trampoline" field. Suggested-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 762806026561..eda69c9f78d0 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1513,7 +1513,7 @@ static void ftrace_remove_tramp(struct ftrace_ops *ops, * The tramp_hash entry will be removed at time * of update. */ - ops->trampolines--; + ops->nr_trampolines--; rec->flags &= ~FTRACE_FL_TRAMP; } @@ -1522,7 +1522,7 @@ static void ftrace_clear_tramps(struct dyn_ftrace *rec) struct ftrace_ops *op; do_for_each_ftrace_op(op, ftrace_ops_list) { - if (op->trampolines) + if (op->nr_trampolines) ftrace_remove_tramp(op, rec); } while_for_each_ftrace_op(op); } @@ -1617,7 +1617,7 @@ static void __ftrace_hash_rec_update(struct ftrace_ops *ops, */ if (ftrace_rec_count(rec) == 1 && ops->trampoline) { rec->flags |= FTRACE_FL_TRAMP; - ops->trampolines++; + ops->nr_trampolines++; } else { /* * If we are adding another function callback @@ -2185,7 +2185,7 @@ static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops) int size, bits; int ret; - size = ops->trampolines; + size = ops->nr_trampolines; bits = 0; /* * Make the hash size about 1/2 the # found @@ -2239,7 +2239,7 @@ static int ftrace_save_tramp_hashes(void) free_ftrace_hash(op->tramp_hash); op->tramp_hash = NULL; - if (op->trampolines) { + if (op->nr_trampolines) { ret = ftrace_save_ops_tramp_hash(op); if (ret) return ret; -- cgit v1.2.3 From 10e83fd01ccbb7122ad2c9dce68fb01bebb3fc46 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Wed, 23 Jul 2014 19:45:12 -0400 Subject: ring-buffer: Use rb_page_size() instead of open coded head_page size There's a helper function to get a ring buffer page size (the number of bytes of data recorded on the page), called rb_page_size(). Use that instead of open coding it. Signed-off-by: Steven Rostedt --- kernel/trace/ring_buffer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 35825a87d6a3..d8c267ec5cca 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -3763,7 +3763,7 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) if (rb_per_cpu_empty(cpu_buffer)) return NULL; - if (iter->head >= local_read(&iter->head_page->page->commit)) { + if (iter->head >= rb_page_size(iter->head_page)) { rb_inc_iter(iter); goto again; } -- cgit v1.2.3 From 2a0343baa4cc0d4e618898f8bdae8136bbb6e1b2 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 24 Jul 2014 09:56:27 -0400 Subject: ftrace: Fix trampoline hash update check on rec->flags In the loop of ftrace_save_ops_tramp_hash(), it adds all the recs to the ops hash if the rec has only one callback attached and the ops is connected to the rec. It gives a nasty warning and shuts down ftrace if the rec doesn't have a trampoline set for it. But this can happen with the following scenario: # cd /sys/kernel/debug/tracing # echo schedule do_IRQ > set_ftrace_filter # mkdir instances/foo # echo schedule > instances/foo/set_ftrace_filter # echo function_graph > current_function # echo function > instances/foo/current_function # echo nop > instances/foo/current_function The above would then trigger the following warning and disable ftrace: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 3145 at kernel/trace/ftrace.c:2212 ftrace_run_update_code+0xe4/0x15b() Modules linked in: ipt_MASQUERADE sunrpc ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ip [...] CPU: 1 PID: 3145 Comm: bash Not tainted 3.16.0-rc3-test+ #136 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./To be filled by O.E.M., BIOS SDBLI944.86P 05/08/2007 0000000000000000 ffffffff81808a88 ffffffff81502130 0000000000000000 ffffffff81040ca1 ffff880077c08000 ffffffff810bd286 0000000000000001 ffffffff81a56830 ffff88007a041be0 ffff88007a872d60 00000000000001be Call Trace: [] ? dump_stack+0x4a/0x75 [] ? warn_slowpath_common+0x7e/0x97 [] ? ftrace_run_update_code+0xe4/0x15b [] ? ftrace_run_update_code+0xe4/0x15b [] ? ftrace_shutdown+0x11c/0x16b [] ? unregister_ftrace_function+0x1e/0x38 [] ? function_trace_reset+0x1a/0x28 [] ? tracing_set_tracer+0xc1/0x276 [] ? tracing_set_trace_write+0x73/0x91 [] ? __sb_start_write+0x9a/0xcc [] ? security_file_permission+0x1b/0x31 [] ? vfs_write+0xac/0x11c [] ? SyS_write+0x60/0x8e [] ? system_call_fastpath+0x16/0x1b ---[ end trace 938c4415cbc7dc96 ]--- ------------[ cut here ]------------ Link: http://lkml.kernel.org/r/20140723120805.GB21376@redhat.com Reported-by: Oleg Nesterov Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index eda69c9f78d0..6ef1989c2b2e 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2208,6 +2208,14 @@ static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops) if (ftrace_rec_count(rec) == 1 && ftrace_ops_test(ops, rec->ip, rec)) { + /* + * If another ops adds to a rec, the rec will + * lose its trampoline and never get it back + * until all ops are off of it. + */ + if (!(rec->flags & FTRACE_FL_TRAMP)) + continue; + /* This record had better have a trampoline */ if (FTRACE_WARN_ON(!(rec->flags & FTRACE_FL_TRAMP_EN))) return -1; -- cgit v1.2.3 From dc6f03f26f570104a2bb03f9d1deb588026d7c75 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Red Hat)" Date: Thu, 24 Jul 2014 11:26:11 -0400 Subject: ftrace: Add warning if tramp hash does not match nr_trampolines After adding all the records to the tramp_hash, add a check that makes sure that the number of records added matches the number of records expected to match and do a WARN_ON and disable ftrace if they do not match. Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 6ef1989c2b2e..979bd8cb4349 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2226,6 +2226,9 @@ static int ftrace_save_ops_tramp_hash(struct ftrace_ops *ops) } } while_for_each_ftrace_rec(); + /* The number of recs in the hash must match nr_trampolines */ + FTRACE_WARN_ON(ops->tramp_hash->count != ops->nr_trampolines); + return 0; } -- cgit v1.2.3