diff options
Diffstat (limited to 'kernel/trace/ftrace.c')
| -rw-r--r-- | kernel/trace/ftrace.c | 613 |
1 files changed, 568 insertions, 45 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5259d4dea675..74439ab5c2b6 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -326,6 +326,8 @@ int __register_ftrace_function(struct ftrace_ops *ops) if (ops->flags & FTRACE_OPS_FL_SAVE_REGS_IF_SUPPORTED) ops->flags |= FTRACE_OPS_FL_SAVE_REGS; #endif + if (!ftrace_enabled && (ops->flags & FTRACE_OPS_FL_PERMANENT)) + return -EBUSY; if (!core_kernel_data((unsigned long)ops)) ops->flags |= FTRACE_OPS_FL_DYNAMIC; @@ -463,10 +465,10 @@ static void *function_stat_start(struct tracer_stat *trace) #ifdef CONFIG_FUNCTION_GRAPH_TRACER /* function graph compares on total time */ -static int function_stat_cmp(void *p1, void *p2) +static int function_stat_cmp(const void *p1, const void *p2) { - struct ftrace_profile *a = p1; - struct ftrace_profile *b = p2; + const struct ftrace_profile *a = p1; + const struct ftrace_profile *b = p2; if (a->time < b->time) return -1; @@ -477,10 +479,10 @@ static int function_stat_cmp(void *p1, void *p2) } #else /* not function graph compares against hits */ -static int function_stat_cmp(void *p1, void *p2) +static int function_stat_cmp(const void *p1, const void *p2) { - struct ftrace_profile *a = p1; - struct ftrace_profile *b = p2; + const struct ftrace_profile *a = p1; + const struct ftrace_profile *b = p2; if (a->counter < b->counter) return -1; @@ -1018,11 +1020,6 @@ static bool update_all_ops; # error Dynamic ftrace depends on MCOUNT_RECORD #endif -struct ftrace_func_entry { - struct hlist_node hlist; - unsigned long ip; -}; - struct ftrace_func_probe { struct ftrace_probe_ops *probe_ops; struct ftrace_ops ops; @@ -1370,24 +1367,16 @@ ftrace_hash_rec_enable_modify(struct ftrace_ops *ops, int filter_hash); static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops, struct ftrace_hash *new_hash); -static struct ftrace_hash * -__ftrace_hash_move(struct ftrace_hash *src) +static struct ftrace_hash *dup_hash(struct ftrace_hash *src, int size) { struct ftrace_func_entry *entry; - struct hlist_node *tn; - struct hlist_head *hhd; struct ftrace_hash *new_hash; - int size = src->count; + struct hlist_head *hhd; + struct hlist_node *tn; int bits = 0; int i; /* - * If the new source is empty, just return the empty_hash. - */ - if (ftrace_hash_empty(src)) - return EMPTY_HASH; - - /* * Make the hash size about 1/2 the # found */ for (size /= 2; size; size >>= 1) @@ -1411,10 +1400,23 @@ __ftrace_hash_move(struct ftrace_hash *src) __add_hash_entry(new_hash, entry); } } - return new_hash; } +static struct ftrace_hash * +__ftrace_hash_move(struct ftrace_hash *src) +{ + int size = src->count; + + /* + * If the new source is empty, just return the empty_hash. + */ + if (ftrace_hash_empty(src)) + return EMPTY_HASH; + + return dup_hash(src, size); +} + static int ftrace_hash_move(struct ftrace_ops *ops, int enable, struct ftrace_hash **dst, struct ftrace_hash *src) @@ -1534,6 +1536,26 @@ static int ftrace_cmp_recs(const void *a, const void *b) return 0; } +static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end) +{ + struct ftrace_page *pg; + struct dyn_ftrace *rec = NULL; + struct dyn_ftrace key; + + key.ip = start; + key.flags = end; /* overload flags, as it is unsigned long */ + + for (pg = ftrace_pages_start; pg; pg = pg->next) { + if (end < pg->records[0].ip || + start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) + continue; + rec = bsearch(&key, pg->records, pg->index, + sizeof(struct dyn_ftrace), + ftrace_cmp_recs); + } + return rec; +} + /** * ftrace_location_range - return the first address of a traced location * if it touches the given ip range @@ -1548,23 +1570,11 @@ static int ftrace_cmp_recs(const void *a, const void *b) */ unsigned long ftrace_location_range(unsigned long start, unsigned long end) { - struct ftrace_page *pg; struct dyn_ftrace *rec; - struct dyn_ftrace key; - - key.ip = start; - key.flags = end; /* overload flags, as it is unsigned long */ - for (pg = ftrace_pages_start; pg; pg = pg->next) { - if (end < pg->records[0].ip || - start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) - continue; - rec = bsearch(&key, pg->records, pg->index, - sizeof(struct dyn_ftrace), - ftrace_cmp_recs); - if (rec) - return rec->ip; - } + rec = lookup_rec(start, end); + if (rec) + return rec->ip; return 0; } @@ -1715,6 +1725,9 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops, if (FTRACE_WARN_ON(ftrace_rec_count(rec) == FTRACE_REF_MAX)) return false; + if (ops->flags & FTRACE_OPS_FL_DIRECT) + rec->flags |= FTRACE_FL_DIRECT; + /* * If there's only a single callback registered to a * function, and the ops has a trampoline registered @@ -1743,6 +1756,15 @@ static bool __ftrace_hash_rec_update(struct ftrace_ops *ops, rec->flags--; /* + * Only the internal direct_ops should have the + * DIRECT flag set. Thus, if it is removing a + * function, then that function should no longer + * be direct. + */ + if (ops->flags & FTRACE_OPS_FL_DIRECT) + rec->flags &= ~FTRACE_FL_DIRECT; + + /* * 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. @@ -2077,15 +2099,34 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update) * 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. + * Same for direct calls. */ if (flag) { - if (!(rec->flags & FTRACE_FL_REGS) != + if (!(rec->flags & FTRACE_FL_REGS) != !(rec->flags & FTRACE_FL_REGS_EN)) flag |= FTRACE_FL_REGS; - if (!(rec->flags & FTRACE_FL_TRAMP) != + if (!(rec->flags & FTRACE_FL_TRAMP) != !(rec->flags & FTRACE_FL_TRAMP_EN)) flag |= FTRACE_FL_TRAMP; + + /* + * Direct calls are special, as count matters. + * We must test the record for direct, if the + * DIRECT and DIRECT_EN do not match, but only + * if the count is 1. That's because, if the + * count is something other than one, we do not + * want the direct enabled (it will be done via the + * direct helper). But if DIRECT_EN is set, and + * the count is not one, we need to clear it. + */ + if (ftrace_rec_count(rec) == 1) { + if (!(rec->flags & FTRACE_FL_DIRECT) != + !(rec->flags & FTRACE_FL_DIRECT_EN)) + flag |= FTRACE_FL_DIRECT; + } else if (rec->flags & FTRACE_FL_DIRECT_EN) { + flag |= FTRACE_FL_DIRECT; + } } /* If the state of this record hasn't changed, then do nothing */ @@ -2110,6 +2151,25 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update) else rec->flags &= ~FTRACE_FL_TRAMP_EN; } + if (flag & FTRACE_FL_DIRECT) { + /* + * If there's only one user (direct_ops helper) + * then we can call the direct function + * directly (no ftrace trampoline). + */ + if (ftrace_rec_count(rec) == 1) { + if (rec->flags & FTRACE_FL_DIRECT) + rec->flags |= FTRACE_FL_DIRECT_EN; + else + rec->flags &= ~FTRACE_FL_DIRECT_EN; + } else { + /* + * Can only call directly if there's + * only one callback to the function. + */ + rec->flags &= ~FTRACE_FL_DIRECT_EN; + } + } } /* @@ -2139,7 +2199,7 @@ static int ftrace_check_record(struct dyn_ftrace *rec, bool enable, bool update) * and REGS states. The _EN flags must be disabled though. */ rec->flags &= ~(FTRACE_FL_ENABLED | FTRACE_FL_TRAMP_EN | - FTRACE_FL_REGS_EN); + FTRACE_FL_REGS_EN | FTRACE_FL_DIRECT_EN); } ftrace_bug_type = FTRACE_BUG_NOP; @@ -2294,6 +2354,52 @@ ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) return NULL; } +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +/* Protected by rcu_tasks for reading, and direct_mutex for writing */ +static struct ftrace_hash *direct_functions = EMPTY_HASH; +static DEFINE_MUTEX(direct_mutex); +int ftrace_direct_func_count; + +/* + * Search the direct_functions hash to see if the given instruction pointer + * has a direct caller attached to it. + */ +static unsigned long find_rec_direct(unsigned long ip) +{ + struct ftrace_func_entry *entry; + + entry = __ftrace_lookup_ip(direct_functions, ip); + if (!entry) + return 0; + + return entry->direct; +} + +static void call_direct_funcs(unsigned long ip, unsigned long pip, + struct ftrace_ops *ops, struct pt_regs *regs) +{ + unsigned long addr; + + addr = find_rec_direct(ip); + if (!addr) + return; + + arch_ftrace_set_direct_caller(regs, addr); +} + +struct ftrace_ops direct_ops = { + .func = call_direct_funcs, + .flags = FTRACE_OPS_FL_IPMODIFY | FTRACE_OPS_FL_RECURSION_SAFE + | FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS + | FTRACE_OPS_FL_PERMANENT, +}; +#else +static inline unsigned long find_rec_direct(unsigned long ip) +{ + return 0; +} +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + /** * ftrace_get_addr_new - Get the call address to set to * @rec: The ftrace record descriptor @@ -2307,6 +2413,15 @@ ftrace_find_tramp_ops_new(struct dyn_ftrace *rec) unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) { struct ftrace_ops *ops; + unsigned long addr; + + if ((rec->flags & FTRACE_FL_DIRECT) && + (ftrace_rec_count(rec) == 1)) { + addr = find_rec_direct(rec->ip); + if (addr) + return addr; + WARN_ON_ONCE(1); + } /* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP) { @@ -2339,6 +2454,15 @@ unsigned long ftrace_get_addr_new(struct dyn_ftrace *rec) unsigned long ftrace_get_addr_curr(struct dyn_ftrace *rec) { struct ftrace_ops *ops; + unsigned long addr; + + /* Direct calls take precedence over trampolines */ + if (rec->flags & FTRACE_FL_DIRECT_EN) { + addr = find_rec_direct(rec->ip); + if (addr) + return addr; + WARN_ON_ONCE(1); + } /* Trampolines take precedence over regs */ if (rec->flags & FTRACE_FL_TRAMP_EN) { @@ -2861,6 +2985,8 @@ static void ftrace_shutdown_sysctl(void) static u64 ftrace_update_time; unsigned long ftrace_update_tot_cnt; +unsigned long ftrace_number_of_pages; +unsigned long ftrace_number_of_groups; static inline int ops_traces_mod(struct ftrace_ops *ops) { @@ -2985,6 +3111,9 @@ static int ftrace_allocate_records(struct ftrace_page *pg, int count) goto again; } + ftrace_number_of_pages += 1 << order; + ftrace_number_of_groups++; + cnt = (PAGE_SIZE << order) / ENTRY_SIZE; pg->size = cnt; @@ -3040,6 +3169,8 @@ ftrace_allocate_pages(unsigned long num_to_init) start_pg = pg->next; kfree(pg); pg = start_pg; + ftrace_number_of_pages -= 1 << order; + ftrace_number_of_groups--; } pr_info("ftrace: FAILED to allocate memory for functions\n"); return NULL; @@ -3450,10 +3581,11 @@ static int t_show(struct seq_file *m, void *v) if (iter->flags & FTRACE_ITER_ENABLED) { struct ftrace_ops *ops; - seq_printf(m, " (%ld)%s%s", + seq_printf(m, " (%ld)%s%s%s", ftrace_rec_count(rec), rec->flags & FTRACE_FL_REGS ? " R" : " ", - rec->flags & FTRACE_FL_IPMODIFY ? " I" : " "); + rec->flags & FTRACE_FL_IPMODIFY ? " I" : " ", + rec->flags & FTRACE_FL_DIRECT ? " D" : " "); if (rec->flags & FTRACE_FL_TRAMP_EN) { ops = ftrace_find_tramp_ops_any(rec); if (ops) { @@ -3469,6 +3601,13 @@ static int t_show(struct seq_file *m, void *v) } else { add_trampoline_func(m, NULL, rec); } + if (rec->flags & FTRACE_FL_DIRECT) { + unsigned long direct; + + direct = find_rec_direct(rec->ip); + if (direct) + seq_printf(m, "\n\tdirect-->%pS", (void *)direct); + } } seq_putc(m, '\n'); @@ -4800,6 +4939,366 @@ ftrace_set_addr(struct ftrace_ops *ops, unsigned long ip, int remove, return ftrace_set_hash(ops, NULL, 0, ip, remove, reset, enable); } +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + +struct ftrace_direct_func { + struct list_head next; + unsigned long addr; + int count; +}; + +static LIST_HEAD(ftrace_direct_funcs); + +/** + * ftrace_find_direct_func - test an address if it is a registered direct caller + * @addr: The address of a registered direct caller + * + * This searches to see if a ftrace direct caller has been registered + * at a specific address, and if so, it returns a descriptor for it. + * + * This can be used by architecture code to see if an address is + * a direct caller (trampoline) attached to a fentry/mcount location. + * This is useful for the function_graph tracer, as it may need to + * do adjustments if it traced a location that also has a direct + * trampoline attached to it. + */ +struct ftrace_direct_func *ftrace_find_direct_func(unsigned long addr) +{ + struct ftrace_direct_func *entry; + bool found = false; + + /* May be called by fgraph trampoline (protected by rcu tasks) */ + list_for_each_entry_rcu(entry, &ftrace_direct_funcs, next) { + if (entry->addr == addr) { + found = true; + break; + } + } + if (found) + return entry; + + return NULL; +} + +/** + * register_ftrace_direct - Call a custom trampoline directly + * @ip: The address of the nop at the beginning of a function + * @addr: The address of the trampoline to call at @ip + * + * This is used to connect a direct call from the nop location (@ip) + * at the start of ftrace traced functions. The location that it calls + * (@addr) must be able to handle a direct call, and save the parameters + * of the function being traced, and restore them (or inject new ones + * if needed), before returning. + * + * Returns: + * 0 on success + * -EBUSY - Another direct function is already attached (there can be only one) + * -ENODEV - @ip does not point to a ftrace nop location (or not supported) + * -ENOMEM - There was an allocation failure. + */ +int register_ftrace_direct(unsigned long ip, unsigned long addr) +{ + struct ftrace_direct_func *direct; + struct ftrace_func_entry *entry; + struct ftrace_hash *free_hash = NULL; + struct dyn_ftrace *rec; + int ret = -EBUSY; + + mutex_lock(&direct_mutex); + + /* See if there's a direct function at @ip already */ + if (find_rec_direct(ip)) + goto out_unlock; + + ret = -ENODEV; + rec = lookup_rec(ip, ip); + if (!rec) + goto out_unlock; + + /* + * Check if the rec says it has a direct call but we didn't + * find one earlier? + */ + if (WARN_ON(rec->flags & FTRACE_FL_DIRECT)) + goto out_unlock; + + /* Make sure the ip points to the exact record */ + if (ip != rec->ip) { + ip = rec->ip; + /* Need to check this ip for a direct. */ + if (find_rec_direct(ip)) + goto out_unlock; + } + + ret = -ENOMEM; + if (ftrace_hash_empty(direct_functions) || + direct_functions->count > 2 * (1 << direct_functions->size_bits)) { + struct ftrace_hash *new_hash; + int size = ftrace_hash_empty(direct_functions) ? 0 : + direct_functions->count + 1; + + if (size < 32) + size = 32; + + new_hash = dup_hash(direct_functions, size); + if (!new_hash) + goto out_unlock; + + free_hash = direct_functions; + direct_functions = new_hash; + } + + entry = kmalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + goto out_unlock; + + direct = ftrace_find_direct_func(addr); + if (!direct) { + direct = kmalloc(sizeof(*direct), GFP_KERNEL); + if (!direct) { + kfree(entry); + goto out_unlock; + } + direct->addr = addr; + direct->count = 0; + list_add_rcu(&direct->next, &ftrace_direct_funcs); + ftrace_direct_func_count++; + } + + entry->ip = ip; + entry->direct = addr; + __add_hash_entry(direct_functions, entry); + + ret = ftrace_set_filter_ip(&direct_ops, ip, 0, 0); + if (ret) + remove_hash_entry(direct_functions, entry); + + if (!ret && !(direct_ops.flags & FTRACE_OPS_FL_ENABLED)) { + ret = register_ftrace_function(&direct_ops); + if (ret) + ftrace_set_filter_ip(&direct_ops, ip, 1, 0); + } + + if (ret) { + kfree(entry); + if (!direct->count) { + list_del_rcu(&direct->next); + synchronize_rcu_tasks(); + kfree(direct); + if (free_hash) + free_ftrace_hash(free_hash); + free_hash = NULL; + ftrace_direct_func_count--; + } + } else { + direct->count++; + } + out_unlock: + mutex_unlock(&direct_mutex); + + if (free_hash) { + synchronize_rcu_tasks(); + free_ftrace_hash(free_hash); + } + + return ret; +} +EXPORT_SYMBOL_GPL(register_ftrace_direct); + +static struct ftrace_func_entry *find_direct_entry(unsigned long *ip, + struct dyn_ftrace **recp) +{ + struct ftrace_func_entry *entry; + struct dyn_ftrace *rec; + + rec = lookup_rec(*ip, *ip); + if (!rec) + return NULL; + + entry = __ftrace_lookup_ip(direct_functions, rec->ip); + if (!entry) { + WARN_ON(rec->flags & FTRACE_FL_DIRECT); + return NULL; + } + + WARN_ON(!(rec->flags & FTRACE_FL_DIRECT)); + + /* Passed in ip just needs to be on the call site */ + *ip = rec->ip; + + if (recp) + *recp = rec; + + return entry; +} + +int unregister_ftrace_direct(unsigned long ip, unsigned long addr) +{ + struct ftrace_direct_func *direct; + struct ftrace_func_entry *entry; + int ret = -ENODEV; + + mutex_lock(&direct_mutex); + + entry = find_direct_entry(&ip, NULL); + if (!entry) + goto out_unlock; + + if (direct_functions->count == 1) + unregister_ftrace_function(&direct_ops); + + ret = ftrace_set_filter_ip(&direct_ops, ip, 1, 0); + + WARN_ON(ret); + + remove_hash_entry(direct_functions, entry); + + direct = ftrace_find_direct_func(addr); + if (!WARN_ON(!direct)) { + /* This is the good path (see the ! before WARN) */ + direct->count--; + WARN_ON(direct->count < 0); + if (!direct->count) { + list_del_rcu(&direct->next); + synchronize_rcu_tasks(); + kfree(direct); + ftrace_direct_func_count--; + } + } + out_unlock: + mutex_unlock(&direct_mutex); + + return ret; +} +EXPORT_SYMBOL_GPL(unregister_ftrace_direct); + +static struct ftrace_ops stub_ops = { + .func = ftrace_stub, +}; + +/** + * ftrace_modify_direct_caller - modify ftrace nop directly + * @entry: The ftrace hash entry of the direct helper for @rec + * @rec: The record representing the function site to patch + * @old_addr: The location that the site at @rec->ip currently calls + * @new_addr: The location that the site at @rec->ip should call + * + * An architecture may overwrite this function to optimize the + * changing of the direct callback on an ftrace nop location. + * This is called with the ftrace_lock mutex held, and no other + * ftrace callbacks are on the associated record (@rec). Thus, + * it is safe to modify the ftrace record, where it should be + * currently calling @old_addr directly, to call @new_addr. + * + * Safety checks should be made to make sure that the code at + * @rec->ip is currently calling @old_addr. And this must + * also update entry->direct to @new_addr. + */ +int __weak ftrace_modify_direct_caller(struct ftrace_func_entry *entry, + struct dyn_ftrace *rec, + unsigned long old_addr, + unsigned long new_addr) +{ + unsigned long ip = rec->ip; + int ret; + + /* + * The ftrace_lock was used to determine if the record + * had more than one registered user to it. If it did, + * we needed to prevent that from changing to do the quick + * switch. But if it did not (only a direct caller was attached) + * then this function is called. But this function can deal + * with attached callers to the rec that we care about, and + * since this function uses standard ftrace calls that take + * the ftrace_lock mutex, we need to release it. + */ + mutex_unlock(&ftrace_lock); + + /* + * By setting a stub function at the same address, we force + * the code to call the iterator and the direct_ops helper. + * This means that @ip does not call the direct call, and + * we can simply modify it. + */ + ret = ftrace_set_filter_ip(&stub_ops, ip, 0, 0); + if (ret) + goto out_lock; + + ret = register_ftrace_function(&stub_ops); + if (ret) { + ftrace_set_filter_ip(&stub_ops, ip, 1, 0); + goto out_lock; + } + + entry->direct = new_addr; + + /* + * By removing the stub, we put back the direct call, calling + * the @new_addr. + */ + unregister_ftrace_function(&stub_ops); + ftrace_set_filter_ip(&stub_ops, ip, 1, 0); + + out_lock: + mutex_lock(&ftrace_lock); + + return ret; +} + +/** + * modify_ftrace_direct - Modify an existing direct call to call something else + * @ip: The instruction pointer to modify + * @old_addr: The address that the current @ip calls directly + * @new_addr: The address that the @ip should call + * + * This modifies a ftrace direct caller at an instruction pointer without + * having to disable it first. The direct call will switch over to the + * @new_addr without missing anything. + * + * Returns: zero on success. Non zero on error, which includes: + * -ENODEV : the @ip given has no direct caller attached + * -EINVAL : the @old_addr does not match the current direct caller + */ +int modify_ftrace_direct(unsigned long ip, + unsigned long old_addr, unsigned long new_addr) +{ + struct ftrace_func_entry *entry; + struct dyn_ftrace *rec; + int ret = -ENODEV; + + mutex_lock(&direct_mutex); + + mutex_lock(&ftrace_lock); + entry = find_direct_entry(&ip, &rec); + if (!entry) + goto out_unlock; + + ret = -EINVAL; + if (entry->direct != old_addr) + goto out_unlock; + + /* + * If there's no other ftrace callback on the rec->ip location, + * then it can be changed directly by the architecture. + * If there is another caller, then we just need to change the + * direct caller helper to point to @new_addr. + */ + if (ftrace_rec_count(rec) == 1) { + ret = ftrace_modify_direct_caller(entry, rec, old_addr, new_addr); + } else { + entry->direct = new_addr; + ret = 0; + } + + out_unlock: + mutex_unlock(&ftrace_lock); + mutex_unlock(&direct_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(modify_ftrace_direct); +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + /** * ftrace_set_filter_ip - set a function to filter on in ftrace by address * @ops - the ops to set the filter with @@ -5818,6 +6317,8 @@ void ftrace_release_mod(struct module *mod) free_pages((unsigned long)pg->records, order); tmp_page = pg->next; kfree(pg); + ftrace_number_of_pages -= 1 << order; + ftrace_number_of_groups--; } } @@ -6159,6 +6660,8 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr) *last_pg = pg->next; order = get_count_order(pg->size / ENTRIES_PER_PAGE); free_pages((unsigned long)pg->records, order); + ftrace_number_of_pages -= 1 << order; + ftrace_number_of_groups--; kfree(pg); pg = container_of(last_pg, struct ftrace_page, next); if (!(*last_pg)) @@ -6214,6 +6717,9 @@ void __init ftrace_init(void) __start_mcount_loc, __stop_mcount_loc); + pr_info("ftrace: allocated %ld pages with %ld groups\n", + ftrace_number_of_pages, ftrace_number_of_groups); + set_ftrace_early_filters(); return; @@ -6754,6 +7260,18 @@ int unregister_ftrace_function(struct ftrace_ops *ops) } EXPORT_SYMBOL_GPL(unregister_ftrace_function); +static bool is_permanent_ops_registered(void) +{ + struct ftrace_ops *op; + + do_for_each_ftrace_op(op, ftrace_ops_list) { + if (op->flags & FTRACE_OPS_FL_PERMANENT) + return true; + } while_for_each_ftrace_op(op); + + return false; +} + int ftrace_enable_sysctl(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, @@ -6771,8 +7289,6 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, if (ret || !write || (last_ftrace_enabled == !!ftrace_enabled)) goto out; - last_ftrace_enabled = !!ftrace_enabled; - if (ftrace_enabled) { /* we are starting ftrace again */ @@ -6783,12 +7299,19 @@ ftrace_enable_sysctl(struct ctl_table *table, int write, ftrace_startup_sysctl(); } else { + if (is_permanent_ops_registered()) { + ftrace_enabled = true; + ret = -EBUSY; + goto out; + } + /* stopping ftrace calls (just send to ftrace_stub) */ ftrace_trace_function = ftrace_stub; ftrace_shutdown_sysctl(); } + last_ftrace_enabled = !!ftrace_enabled; out: mutex_unlock(&ftrace_lock); return ret; |