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2021-07-02Merge tag 'powerpc-5.14-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: - A big series refactoring parts of our KVM code, and converting some to C. - Support for ARCH_HAS_SET_MEMORY, and ARCH_HAS_STRICT_MODULE_RWX on some CPUs. - Support for the Microwatt soft-core. - Optimisations to our interrupt return path on 64-bit. - Support for userspace access to the NX GZIP accelerator on PowerVM on Power10. - Enable KUAP and KUEP by default on 32-bit Book3S CPUs. - Other smaller features, fixes & cleanups. Thanks to: Andy Shevchenko, Aneesh Kumar K.V, Arnd Bergmann, Athira Rajeev, Baokun Li, Benjamin Herrenschmidt, Bharata B Rao, Christophe Leroy, Daniel Axtens, Daniel Henrique Barboza, Finn Thain, Geoff Levand, Haren Myneni, Jason Wang, Jiapeng Chong, Joel Stanley, Jordan Niethe, Kajol Jain, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Nick Desaulniers, Paul Mackerras, Russell Currey, Sathvika Vasireddy, Shaokun Zhang, Stephen Rothwell, Sudeep Holla, Suraj Jitindar Singh, Tom Rix, Vaibhav Jain, YueHaibing, Zhang Jianhua, and Zhen Lei. * tag 'powerpc-5.14-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (218 commits) powerpc: Only build restart_table.c for 64s powerpc/64s: move ret_from_fork etc above __end_soft_masked powerpc/64s/interrupt: clean up interrupt return labels powerpc/64/interrupt: add missing kprobe annotations on interrupt exit symbols powerpc/64: enable MSR[EE] in irq replay pt_regs powerpc/64s/interrupt: preserve regs->softe for NMI interrupts powerpc/64s: add a table of implicit soft-masked addresses powerpc/64e: remove implicit soft-masking and interrupt exit restart logic powerpc/64e: fix CONFIG_RELOCATABLE build warnings powerpc/64s: fix hash page fault interrupt handler powerpc/4xx: Fix setup_kuep() on SMP powerpc/32s: Fix setup_{kuap/kuep}() on SMP powerpc/interrupt: Use names in check_return_regs_valid() powerpc/interrupt: Also use exit_must_hard_disable() on PPC32 powerpc/sysfs: Replace sizeof(arr)/sizeof(arr[0]) with ARRAY_SIZE powerpc/ptrace: Refactor regs_set_return_{msr/ip} powerpc/ptrace: Move set_return_regs_changed() before regs_set_return_{msr/ip} powerpc/stacktrace: Fix spurious "stale" traces in raise_backtrace_ipi() powerpc/pseries/vas: Include irqdomain.h powerpc: mark local variables around longjmp as volatile ...
2021-07-02Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge more updates from Andrew Morton: "190 patches. Subsystems affected by this patch series: mm (hugetlb, userfaultfd, vmscan, kconfig, proc, z3fold, zbud, ras, mempolicy, memblock, migration, thp, nommu, kconfig, madvise, memory-hotplug, zswap, zsmalloc, zram, cleanups, kfence, and hmm), procfs, sysctl, misc, core-kernel, lib, lz4, checkpatch, init, kprobes, nilfs2, hfs, signals, exec, kcov, selftests, compress/decompress, and ipc" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (190 commits) ipc/util.c: use binary search for max_idx ipc/sem.c: use READ_ONCE()/WRITE_ONCE() for use_global_lock ipc: use kmalloc for msg_queue and shmid_kernel ipc sem: use kvmalloc for sem_undo allocation lib/decompressors: remove set but not used variabled 'level' selftests/vm/pkeys: exercise x86 XSAVE init state selftests/vm/pkeys: refill shadow register after implicit kernel write selftests/vm/pkeys: handle negative sys_pkey_alloc() return code selftests/vm/pkeys: fix alloc_random_pkey() to make it really, really random kcov: add __no_sanitize_coverage to fix noinstr for all architectures exec: remove checks in __register_bimfmt() x86: signal: don't do sas_ss_reset() until we are certain that sigframe won't be abandoned hfsplus: report create_date to kstat.btime hfsplus: remove unnecessary oom message nilfs2: remove redundant continue statement in a while-loop kprobes: remove duplicated strong free_insn_page in x86 and s390 init: print out unknown kernel parameters checkpatch: do not complain about positive return values starting with EPOLL checkpatch: improve the indented label test checkpatch: scripts/spdxcheck.py now requires python3 ...
2021-07-01kprobes: remove duplicated strong free_insn_page in x86 and s390Barry Song
free_insn_page() in x86 and s390 is same with the common weak function in kernel/kprobes.c. Plus, the comment "Recover page to RW mode before releasing it" in x86 seems insensible to be there since resetting mapping is done by common code in vfree() of module_memfree(). So drop these two duplicated strong functions and related comment, then mark the common one in kernel/kprobes.c strong. Link: https://lkml.kernel.org/r/20210608065736.32656-1-song.bao.hua@hisilicon.com Signed-off-by: Barry Song <song.bao.hua@hisilicon.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Heiko Carstens <hca@linux.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Qi Liu <liuqi115@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-06-01kprobes: Remove kprobe::fault_handlerPeter Zijlstra
The reason for kprobe::fault_handler(), as given by their comment: * We come here because instructions in the pre/post * handler caused the page_fault, this could happen * if handler tries to access user space by * copy_from_user(), get_user() etc. Let the * user-specified handler try to fix it first. Is just plain bad. Those other handlers are ran from non-preemptible context and had better use _nofault() functions. Also, there is no upstream usage of this. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org
2021-05-23kprobes: Allow architectures to override optinsn page allocationChristophe Leroy
Some architectures like powerpc require a non standard allocation of optinsn page, because module pages are too far from the kernel for direct branches. Define weak alloc_optinsn_page() and free_optinsn_page(), that fall back on alloc_insn_page() and free_insn_page() when not overridden by the architecture. Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/40a43d6df1fdf41ade36e9a46e60a4df774ca9f6.1620896780.git.christophe.leroy@csgroup.eu
2021-01-29tracing/kprobe: Fix to support kretprobe events on unloaded modulesMasami Hiramatsu
Fix kprobe_on_func_entry() returns error code instead of false so that register_kretprobe() can return an appropriate error code. append_trace_kprobe() expects the kprobe registration returns -ENOENT when the target symbol is not found, and it checks whether the target module is unloaded or not. If the target module doesn't exist, it defers to probe the target symbol until the module is loaded. However, since register_kretprobe() returns -EINVAL instead of -ENOENT in that case, it always fail on putting the kretprobe event on unloaded modules. e.g. Kprobe event: /sys/kernel/debug/tracing # echo p xfs:xfs_end_io >> kprobe_events [ 16.515574] trace_kprobe: This probe might be able to register after target module is loaded. Continue. Kretprobe event: (p -> r) /sys/kernel/debug/tracing # echo r xfs:xfs_end_io >> kprobe_events sh: write error: Invalid argument /sys/kernel/debug/tracing # cat error_log [ 41.122514] trace_kprobe: error: Failed to register probe event Command: r xfs:xfs_end_io ^ To fix this bug, change kprobe_on_func_entry() to detect symbol lookup failure and return -ENOENT in that case. Otherwise it returns -EINVAL or 0 (succeeded, given address is on the entry). Link: https://lkml.kernel.org/r/161176187132.1067016.8118042342894378981.stgit@devnote2 Cc: stable@vger.kernel.org Fixes: 59158ec4aef7 ("tracing/kprobes: Check the probe on unloaded module correctly") Reported-by: Jianlin Lv <Jianlin.Lv@arm.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-12-17Merge tag 'trace-v5.11' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "The major update to this release is that there's a new arch config option called CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS. Currently, only x86_64 enables it. All the ftrace callbacks now take a struct ftrace_regs instead of a struct pt_regs. If the architecture has HAVE_DYNAMIC_FTRACE_WITH_ARGS enabled, then the ftrace_regs will have enough information to read the arguments of the function being traced, as well as access to the stack pointer. This way, if a user (like live kernel patching) only cares about the arguments, then it can avoid using the heavier weight "regs" callback, that puts in enough information in the struct ftrace_regs to simulate a breakpoint exception (needed for kprobes). A new config option that audits the timestamps of the ftrace ring buffer at most every event recorded. Ftrace recursion protection has been cleaned up to move the protection to the callback itself (this saves on an extra function call for those callbacks). Perf now handles its own RCU protection and does not depend on ftrace to do it for it (saving on that extra function call). New debug option to add "recursed_functions" file to tracefs that lists all the places that triggered the recursion protection of the function tracer. This will show where things need to be fixed as recursion slows down the function tracer. The eval enum mapping updates done at boot up are now offloaded to a work queue, as it caused a noticeable pause on slow embedded boards. Various clean ups and last minute fixes" * tag 'trace-v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (33 commits) tracing: Offload eval map updates to a work queue Revert: "ring-buffer: Remove HAVE_64BIT_ALIGNED_ACCESS" ring-buffer: Add rb_check_bpage in __rb_allocate_pages ring-buffer: Fix two typos in comments tracing: Drop unneeded assignment in ring_buffer_resize() tracing: Disable ftrace selftests when any tracer is running seq_buf: Avoid type mismatch for seq_buf_init ring-buffer: Fix a typo in function description ring-buffer: Remove obsolete rb_event_is_commit() ring-buffer: Add test to validate the time stamp deltas ftrace/documentation: Fix RST C code blocks tracing: Clean up after filter logic rewriting tracing: Remove the useless value assignment in test_create_synth_event() livepatch: Use the default ftrace_ops instead of REGS when ARGS is available ftrace/x86: Allow for arguments to be passed in to ftrace_regs by default ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regs MAINTAINERS: assign ./fs/tracefs to TRACING tracing: Fix some typos in comments ftrace: Remove unused varible 'ret' ring-buffer: Add recording of ring buffer recursion into recursed_functions ...
2020-11-13ftrace: Have the callbacks receive a struct ftrace_regs instead of pt_regsSteven Rostedt (VMware)
In preparation to have arguments of a function passed to callbacks attached to functions as default, change the default callback prototype to receive a struct ftrace_regs as the forth parameter instead of a pt_regs. For callbacks that set the FL_SAVE_REGS flag in their ftrace_ops flags, they will now need to get the pt_regs via a ftrace_get_regs() helper call. If this is called by a callback that their ftrace_ops did not have a FL_SAVE_REGS flag set, it that helper function will return NULL. This will allow the ftrace_regs to hold enough just to get the parameters and stack pointer, but without the worry that callbacks may have a pt_regs that is not completely filled. Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-11-07Merge branch 'linus' into perf/kprobesIngo Molnar
Merge recent kprobes updates into perf/kprobes that came from -mm. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-10-12Merge tag 'perf-kprobes-2020-10-12' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf/kprobes updates from Ingo Molnar: "This prepares to unify the kretprobe trampoline handler and make kretprobe lockless (those patches are still work in progress)" * tag 'perf-kprobes-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: kprobes: Fix to check probe enabled before disarm_kprobe_ftrace() kprobes: Make local functions static kprobes: Free kretprobe_instance with RCU callback kprobes: Remove NMI context check sparc: kprobes: Use generic kretprobe trampoline handler sh: kprobes: Use generic kretprobe trampoline handler s390: kprobes: Use generic kretprobe trampoline handler powerpc: kprobes: Use generic kretprobe trampoline handler parisc: kprobes: Use generic kretprobe trampoline handler mips: kprobes: Use generic kretprobe trampoline handler ia64: kprobes: Use generic kretprobe trampoline handler csky: kprobes: Use generic kretprobe trampoline handler arc: kprobes: Use generic kretprobe trampoline handler arm64: kprobes: Use generic kretprobe trampoline handler arm: kprobes: Use generic kretprobe trampoline handler x86/kprobes: Use generic kretprobe trampoline handler kprobes: Add generic kretprobe trampoline handler
2020-10-12kprobes: Replace rp->free_instance with freelistPeter Zijlstra
Gets rid of rp->lock, and as a result kretprobes are now fully lockless. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/159870623583.1229682.17472357584134058687.stgit@devnote2
2020-10-12kprobes: Remove kretprobe hashPeter Zijlstra
The kretprobe hash is mostly superfluous, replace it with a per-task variable. This gets rid of the task hash and it's related locking. Note that this may change the kprobes module-exported API for kretprobe handlers. If any out-of-tree kretprobe user uses ri->rp, use get_kretprobe(ri) instead. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/159870620431.1229682.16325792502413731312.stgit@devnote2
2020-09-18kprobes: tracing/kprobes: Fix to kill kprobes on initmem after bootMasami Hiramatsu
Since kprobe_event= cmdline option allows user to put kprobes on the functions in initmem, kprobe has to make such probes gone after boot. Currently the probes on the init functions in modules will be handled by module callback, but the kernel init text isn't handled. Without this, kprobes may access non-exist text area to disable or remove it. Link: https://lkml.kernel.org/r/159972810544.428528.1839307531600646955.stgit@devnote2 Fixes: 970988e19eb0 ("tracing/kprobe: Add kprobe_event= boot parameter") Cc: Jonathan Corbet <corbet@lwn.net> Cc: Shuah Khan <skhan@linuxfoundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-09-08kprobes: Make local functions staticMasami Hiramatsu
Since we unified the kretprobe trampoline handler from arch/* code, some functions and objects do not need to be exported anymore. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/159870618256.1229682.8692046612635810882.stgit@devnote2
2020-09-08kprobes: Free kretprobe_instance with RCU callbackMasami Hiramatsu
Free kretprobe_instance with RCU callback instead of directly freeing the object in the kretprobe handler context. This will make kretprobe run safer in NMI context. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/159870616685.1229682.11978742048709542226.stgit@devnote2
2020-09-08kprobes: Add generic kretprobe trampoline handlerMasami Hiramatsu
Add a generic kretprobe trampoline handler for unifying the all cloned /arch/* kretprobe trampoline handlers. The generic kretprobe trampoline handler is based on the x86 implementation, because it is the latest implementation. It has frame pointer checking, kprobe_busy_begin/end and return address fixup for user handlers. [ mingo: Minor edits. ] Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/159870600138.1229682.3424065380448088833.stgit@devnote2
2020-08-07Merge tag 'trace-v5.9' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: - The biggest news in that the tracing ring buffer can now time events that interrupted other ring buffer events. Before this change, if an interrupt came in while recording another event, and that interrupt also had an event, those events would all have the same time stamp as the event it interrupted. Now, with the new design, those events will have a unique time stamp and rightfully display the time for those events that were recorded while interrupting another event. - Bootconfig how has an "override" operator that lets the users have a default config, but then add options to override the default. - A fix was made to properly filter function graph tracing to the ftrace PIDs. This came in at the end of the -rc cycle, and needs to be backported. - Several clean ups, performance updates, and minor fixes as well. * tag 'trace-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (39 commits) tracing: Add trace_array_init_printk() to initialize instance trace_printk() buffers kprobes: Fix compiler warning for !CONFIG_KPROBES_ON_FTRACE tracing: Use trace_sched_process_free() instead of exit() for pid tracing bootconfig: Fix to find the initargs correctly Documentation: bootconfig: Add bootconfig override operator tools/bootconfig: Add testcases for value override operator lib/bootconfig: Add override operator support kprobes: Remove show_registers() function prototype tracing/uprobe: Remove dead code in trace_uprobe_register() kprobes: Fix NULL pointer dereference at kprobe_ftrace_handler ftrace: Fix ftrace_trace_task return value tracepoint: Use __used attribute definitions from compiler_attributes.h tracepoint: Mark __tracepoint_string's __used trace : Have tracing buffer info use kvzalloc instead of kzalloc tracing: Remove outdated comment in stack handling ftrace: Do not let direct or IPMODIFY ftrace_ops be added to module and set trampolines ftrace: Setup correct FTRACE_FL_REGS flags for module tracing/hwlat: Honor the tracing_cpumask tracing/hwlat: Drop the duplicate assignment in start_kthread() tracing: Save one trace_event->type by using __TRACE_LAST_TYPE ...
2020-08-03kprobes: Remove show_registers() function prototypeMasami Hiramatsu
Remove show_registers() function prototype because this function has been renamed by commit 57da8b960b9a ("x86: Avoid double stack traces with show_regs()"), and commit 80006dbee674 ("kprobes/x86: Remove jprobe implementation") has removed the caller in kprobes. So this doesn't exist anymore. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-07-02Merge branch 'perf/vlbr'Peter Zijlstra
2020-06-20Merge tag 'trace-v5.8-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing fixes from Steven Rostedt: - Have recordmcount work with > 64K sections (to support LTO) - kprobe RCU fixes - Correct a kprobe critical section with missing mutex - Remove redundant arch_disarm_kprobe() call - Fix lockup when kretprobe triggers within kprobe_flush_task() - Fix memory leak in fetch_op_data operations - Fix sleep in atomic in ftrace trace array sample code - Free up memory on failure in sample trace array code - Fix incorrect reporting of function_graph fields in format file - Fix quote within quote parsing in bootconfig - Fix return value of bootconfig tool - Add testcases for bootconfig tool - Fix maybe uninitialized warning in ftrace pid file code - Remove unused variable in tracing_iter_reset() - Fix some typos * tag 'trace-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: ftrace: Fix maybe-uninitialized compiler warning tools/bootconfig: Add testcase for show-command and quotes test tools/bootconfig: Fix to return 0 if succeeded to show the bootconfig tools/bootconfig: Fix to use correct quotes for value proc/bootconfig: Fix to use correct quotes for value tracing: Remove unused event variable in tracing_iter_reset tracing/probe: Fix memleak in fetch_op_data operations trace: Fix typo in allocate_ftrace_ops()'s comment tracing: Make ftrace packed events have align of 1 sample-trace-array: Remove trace_array 'sample-instance' sample-trace-array: Fix sleeping function called from invalid context kretprobe: Prevent triggering kretprobe from within kprobe_flush_task kprobes: Remove redundant arch_disarm_kprobe() call kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex kprobes: Use non RCU traversal APIs on kprobe_tables if possible kprobes: Suppress the suspicious RCU warning on kprobes recordmcount: support >64k sections
2020-06-16kretprobe: Prevent triggering kretprobe from within kprobe_flush_taskJiri Olsa
Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave. My test was also able to trigger lockdep output: ============================================ WARNING: possible recursive locking detected 5.6.0-rc6+ #6 Not tainted -------------------------------------------- sched-messaging/2767 is trying to acquire lock: ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0 but task is already holding lock: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(kretprobe_table_locks[i].lock)); lock(&(kretprobe_table_locks[i].lock)); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by sched-messaging/2767: #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 stack backtrace: CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6 Call Trace: dump_stack+0x96/0xe0 __lock_acquire.cold.57+0x173/0x2b7 ? native_queued_spin_lock_slowpath+0x42b/0x9e0 ? lockdep_hardirqs_on+0x590/0x590 ? __lock_acquire+0xf63/0x4030 lock_acquire+0x15a/0x3d0 ? kretprobe_hash_lock+0x52/0xa0 _raw_spin_lock_irqsave+0x36/0x70 ? kretprobe_hash_lock+0x52/0xa0 kretprobe_hash_lock+0x52/0xa0 trampoline_handler+0xf8/0x940 ? kprobe_fault_handler+0x380/0x380 ? find_held_lock+0x3a/0x1c0 kretprobe_trampoline+0x25/0x50 ? lock_acquired+0x392/0xbc0 ? _raw_spin_lock_irqsave+0x50/0x70 ? __get_valid_kprobe+0x1f0/0x1f0 ? _raw_spin_unlock_irqrestore+0x3b/0x40 ? finish_task_switch+0x4b9/0x6d0 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 The code within the kretprobe handler checks for probe reentrancy, so we won't trigger any _raw_spin_lock_irqsave probe in there. The problem is in outside kprobe_flush_task, where we call: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave where _raw_spin_lock_irqsave triggers the kretprobe and installs kretprobe_trampoline handler on _raw_spin_lock_irqsave return. The kretprobe_trampoline handler is then executed with already locked kretprobe_table_locks, and first thing it does is to lock kretprobe_table_locks ;-) the whole lockup path like: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed ---> kretprobe_table_locks locked kretprobe_trampoline trampoline_handler kretprobe_hash_lock(current, &head, &flags); <--- deadlock Adding kprobe_busy_begin/end helpers that mark code with fake probe installed to prevent triggering of another kprobe within this code. Using these helpers in kprobe_flush_task, so the probe recursion protection check is hit and the probe is never set to prevent above lockup. Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2 Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking") Cc: Ingo Molnar <mingo@kernel.org> Cc: "Gustavo A . R . Silva" <gustavoars@kernel.org> Cc: Anders Roxell <anders.roxell@linaro.org> Cc: "Naveen N . Rao" <naveen.n.rao@linux.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Reported-by: "Ziqian SUN (Zamir)" <zsun@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2020-06-15kprobes: Replace zero-length array with flexible-arrayGustavo A. R. Silva
There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://github.com/KSPP/linux/issues/21 Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-06-15kprobes: Add symbols for kprobe insn pagesAdrian Hunter
Symbols are needed for tools to describe instruction addresses. Pages allocated for kprobe's purposes need symbols to be created for them. Add such symbols to be visible via /proc/kallsyms. Note: kprobe insn pages are not used if ftrace is configured. To see the effect of this patch, the kernel must be configured with: # CONFIG_FUNCTION_TRACER is not set CONFIG_KPROBES=y and for optimised kprobes: CONFIG_OPTPROBES=y Example on x86: # perf probe __schedule Added new event: probe:__schedule (on __schedule) # cat /proc/kallsyms | grep '\[__builtin__kprobes\]' ffffffffc00d4000 t kprobe_insn_page [__builtin__kprobes] ffffffffc00d6000 t kprobe_optinsn_page [__builtin__kprobes] Note: This patch adds "__builtin__kprobes" as a module name in /proc/kallsyms for symbols for pages allocated for kprobes' purposes, even though "__builtin__kprobes" is not a module. Signed-off-by: Adrian Hunter <adrian.hunter@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Link: https://lkml.kernel.org/r/20200528080058.20230-1-adrian.hunter@intel.com
2020-04-27sysctl: pass kernel pointers to ->proc_handlerChristoph Hellwig
Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-07-16mm, kprobes: generalize and rename notify_page_fault() as kprobe_page_fault()Anshuman Khandual
Architectures which support kprobes have very similar boilerplate around calling kprobe_fault_handler(). Use a helper function in kprobes.h to unify them, based on the x86 code. This changes the behaviour for other architectures when preemption is enabled. Previously, they would have disabled preemption while calling the kprobe handler. However, preemption would be disabled if this fault was due to a kprobe, so we know the fault was not due to a kprobe handler and can simply return failure. This behaviour was introduced in commit a980c0ef9f6d ("x86/kprobes: Refactor kprobes_fault() like kprobe_exceptions_notify()") [anshuman.khandual@arm.com: export kprobe_fault_handler()] Link: http://lkml.kernel.org/r/1561133358-8876-1-git-send-email-anshuman.khandual@arm.com Link: http://lkml.kernel.org/r/1560420444-25737-1-git-send-email-anshuman.khandual@arm.com Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com> Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Christophe Leroy <christophe.leroy@c-s.fr> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: James Hogan <jhogan@kernel.org> Cc: Paul Burton <paul.burton@mips.com> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-30treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156Thomas Gleixner
Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not write to the free software foundation inc 59 temple place suite 330 boston ma 02111 1307 usa extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1334 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Reviewed-by: Richard Fontana <rfontana@redhat.com> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-04-19x86/kprobes: Verify stack frame on kretprobeMasami Hiramatsu
Verify the stack frame pointer on kretprobe trampoline handler, If the stack frame pointer does not match, it skips the wrong entry and tries to find correct one. This can happen if user puts the kretprobe on the function which can be used in the path of ftrace user-function call. Such functions should not be probed, so this adds a warning message that reports which function should be blacklisted. Tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/155094059185.6137.15527904013362842072.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2019-01-30x86/hw_breakpoints, kprobes: Remove kprobes ifdefferyBorislav Petkov
Remove the ifdeffery in the breakpoint parsing arch_build_bp_info() by adding a within_kprobe_blacklist() stub for the !CONFIG_KPROBES case. It is returning true when kprobes are not enabled to mean that any address is within the kprobes blacklist on such kernels and thus not allow kernel breakpoints on non-kprobes kernels. Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Frederic Weisbecker <frederic@kernel.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190127131237.4557-1-bp@alien8.de
2018-12-26Merge branch 'x86-cleanups-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 cleanups from Ingo Molnar: "Misc cleanups" * 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/kprobes: Remove trampoline_handler() prototype x86/kernel: Fix more -Wmissing-prototypes warnings x86: Fix various typos in comments x86/headers: Fix -Wmissing-prototypes warning x86/process: Avoid unnecessary NULL check in get_wchan() x86/traps: Complete prototype declarations x86/mce: Fix -Wmissing-prototypes warnings x86/gart: Rewrite early_gart_iommu_check() comment
2018-12-17kprobes: Blacklist symbols in arch-defined prohibited areaMasami Hiramatsu
Blacklist symbols in arch-defined probe-prohibited areas. With this change, user can see all symbols which are prohibited to probe in debugfs. All archtectures which have custom prohibit areas should define its own arch_populate_kprobe_blacklist() function, but unless that, all symbols marked __kprobes are blacklisted. Reported-by: Andrea Righi <righi.andrea@gmail.com> Tested-by: Andrea Righi <righi.andrea@gmail.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Borislav Petkov <bp@alien8.de> Cc: David S. Miller <davem@davemloft.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yonghong Song <yhs@fb.com> Link: http://lkml.kernel.org/r/154503485491.26176.15823229545155174796.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-12-08x86/kernel: Fix more -Wmissing-prototypes warningsBorislav Petkov
... with the goal of eventually enabling -Wmissing-prototypes by default. At least on x86. Make functions static where possible, otherwise add prototypes or make them visible through includes. asm/trace/ changes courtesy of Steven Rostedt <rostedt@goodmis.org>. Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> # ACPI + cpufreq bits Cc: Andrew Banman <andrew.banman@hpe.com> Cc: Dimitri Sivanich <dimitri.sivanich@hpe.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mike Travis <mike.travis@hpe.com> Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yi Wang <wang.yi59@zte.com.cn> Cc: linux-acpi@vger.kernel.org
2018-06-21kprobes: Remove jprobe stub APIMasami Hiramatsu
Remove jprobe stub APIs from linux/kprobes.h since the jprobe implementation was completely gone. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/lkml/152942503572.15209.1652552217914694917.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21kprobes: Remove jprobe API implementationMasami Hiramatsu
Remove functionally empty jprobe API implementations and test cases. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-arch@vger.kernel.org Link: https://lore.kernel.org/lkml/152942430705.15209.2307050500995264322.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-11-13kprobes: Don't spam the build log with deprecation warningsIngo Molnar
The jprobes APIs are deprecated - but are still in occasional use for code that few people seem to care about, so stop generating deprecation warnings. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-20kprobes: Disable the jprobes APIsMasami Hiramatsu
Disable the jprobes APIs and comment out the jprobes API function code. This is in preparation of removing all jprobes related code (including kprobe's break_handler). Nowadays ftrace and other tracing features are mature enough to replace jprobes use-cases. Users can safely use ftrace and perf probe etc. for their use cases. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S . Miller <davem@davemloft.net> Cc: Ian McDonald <ian.mcdonald@jandi.co.nz> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vlad Yasevich <vyasevich@gmail.com> Link: http://lkml.kernel.org/r/150724527741.5014.15465541485637899227.stgit@devbox Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-07-08kprobes: Rename [arch_]function_offset_within_entry() to ↵Naveen N. Rao
[arch_]kprobe_on_func_entry() Rename function_offset_within_entry() to scope it to kprobe namespace by using kprobe_ prefix, and to also simplify it. Suggested-by: Ingo Molnar <mingo@kernel.org> Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/3aa6c7e2e4fb6e00f3c24fa306496a66edb558ea.1499443367.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-05-17tracing/kprobes: Enforce kprobes teardown after testingThomas Gleixner
Enabling the tracer selftest triggers occasionally the warning in text_poke(), which warns when the to be modified page is not marked reserved. The reason is that the tracer selftest installs kprobes on functions marked __init for testing. These probes are removed after the tests, but that removal schedules the delayed kprobes_optimizer work, which will do the actual text poke. If the work is executed after the init text is freed, then the warning triggers. The bug can be reproduced reliably when the work delay is increased. Flush the optimizer work and wait for the optimizing/unoptimizing lists to become empty before returning from the kprobes tracer selftest. That ensures that all operations which were queued due to the probes removal have completed. Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: stable@vger.kernel.org Fixes: 6274de498 ("kprobes: Support delayed unoptimizing") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2017-05-05Merge tag 'powerpc-4.12-1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux Pull powerpc updates from Michael Ellerman: "Highlights include: - Larger virtual address space on 64-bit server CPUs. By default we use a 128TB virtual address space, but a process can request access to the full 512TB by passing a hint to mmap(). - Support for the new Power9 "XIVE" interrupt controller. - TLB flushing optimisations for the radix MMU on Power9. - Support for CAPI cards on Power9, using the "Coherent Accelerator Interface Architecture 2.0". - The ability to configure the mmap randomisation limits at build and runtime. - Several small fixes and cleanups to the kprobes code, as well as support for KPROBES_ON_FTRACE. - Major improvements to handling of system reset interrupts, correctly treating them as NMIs, giving them a dedicated stack and using a new hypervisor call to trigger them, all of which should aid debugging and robustness. - Many fixes and other minor enhancements. Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anshuman Khandual, Anton Blanchard, Balbir Singh, Ben Hutchings, Benjamin Herrenschmidt, Bhupesh Sharma, Chris Packham, Christian Zigotzky, Christophe Leroy, Christophe Lombard, Daniel Axtens, David Gibson, Gautham R. Shenoy, Gavin Shan, Geert Uytterhoeven, Guilherme G. Piccoli, Hamish Martin, Hari Bathini, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Mahesh J Salgaonkar, Mahesh Salgaonkar, Masami Hiramatsu, Matt Brown, Matthew R. Ochs, Michael Neuling, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Pan Xinhui, Paul Mackerras, Rashmica Gupta, Russell Currey, Sukadev Bhattiprolu, Thadeu Lima de Souza Cascardo, Tobin C. Harding, Tyrel Datwyler, Uma Krishnan, Vaibhav Jain, Vipin K Parashar, Yang Shi" * tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (214 commits) powerpc/64s: Power9 has no LPCR[VRMASD] field so don't set it powerpc/powernv: Fix TCE kill on NVLink2 powerpc/mm/radix: Drop support for CPUs without lockless tlbie powerpc/book3s/mce: Move add_taint() later in virtual mode powerpc/sysfs: Move #ifdef CONFIG_HOTPLUG_CPU out of the function body powerpc/smp: Document irq enable/disable after migrating IRQs powerpc/mpc52xx: Don't select user-visible RTAS_PROC powerpc/powernv: Document cxl dependency on special case in pnv_eeh_reset() powerpc/eeh: Clean up and document event handling functions powerpc/eeh: Avoid use after free in eeh_handle_special_event() cxl: Mask slice error interrupts after first occurrence cxl: Route eeh events to all drivers in cxl_pci_error_detected() cxl: Force context lock during EEH flow powerpc/64: Allow CONFIG_RELOCATABLE if COMPILE_TEST powerpc/xmon: Teach xmon oops about radix vectors powerpc/mm/hash: Fix off-by-one in comment about kernel contexts ids powerpc/pseries: Enable VFIO powerpc/powernv: Fix iommu table size calculation hook for small tables powerpc/powernv: Check kzalloc() return value in pnv_pci_table_alloc powerpc: Add arch/powerpc/tools directory ...
2017-04-20powerpc/kprobes: Fix handling of function offsets on ABIv2Naveen N. Rao
commit 239aeba76409 ("perf powerpc: Fix kprobe and kretprobe handling with kallsyms on ppc64le") changed how we use the offset field in struct kprobe on ABIv2. perf now offsets from the global entry point if an offset is specified and otherwise chooses the local entry point. Fix the same in kernel for kprobe API users. We do this by extending kprobe_lookup_name() to accept an additional parameter to indicate the offset specified with the kprobe registration. If offset is 0, we return the local function entry and return the global entry point otherwise. With: # cd /sys/kernel/debug/tracing/ # echo "p _do_fork" >> kprobe_events # echo "p _do_fork+0x10" >> kprobe_events before this patch: # cat ../kprobes/list c0000000000d0748 k _do_fork+0x8 [DISABLED] c0000000000d0758 k _do_fork+0x18 [DISABLED] c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] and after: # cat ../kprobes/list c0000000000d04c8 k _do_fork+0x8 [DISABLED] c0000000000d04d0 k _do_fork+0x10 [DISABLED] c0000000000412b0 k kretprobe_trampoline+0x0 [OPTIMIZED] Acked-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-04-20kprobes: Convert kprobe_lookup_name() to a functionNaveen N. Rao
The macro is now pretty long and ugly on powerpc. In the light of further changes needed here, convert it to a __weak variant to be over-ridden with a nicer looking function. Suggested-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2017-03-15trace/kprobes: Fix check for kretprobe offset within function entryNaveen N. Rao
perf specifies an offset from _text and since this offset is fed directly into the arch-specific helper, kprobes tracer rejects installation of kretprobes through perf. Fix this by looking up the actual offset from a function for the specified sym+offset. Refactor and reuse existing routines to limit code duplication -- we repurpose kprobe_addr() for determining final kprobe address and we split out the function entry offset determination into a separate generic helper. Before patch: naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return probe-definition(0): do_open%return symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /boot/vmlinux for symbols Open Debuginfo file: /boot/vmlinux Try to find probe point from debuginfo. Matched function: do_open [2d0c7ff] Probe point found: do_open+0 Matched function: do_open [35d76dc] found inline addr: 0xc0000000004ba9c4 Failed to find "do_open%return", because do_open is an inlined function and has no return point. An error occurred in debuginfo analysis (-22). Trying to use symbols. Opening /sys/kernel/debug/tracing//README write=0 Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: r:probe/do_open _text+4469776 Failed to write event: Invalid argument Error: Failed to add events. Reason: Invalid argument (Code: -22) naveen@ubuntu:~/linux/tools/perf$ dmesg | tail <snip> [ 33.568656] Given offset is not valid for return probe. After patch: naveen@ubuntu:~/linux/tools/perf$ sudo ./perf probe -v do_open%return probe-definition(0): do_open%return symbol:do_open file:(null) line:0 offset:0 return:1 lazy:(null) 0 arguments Looking at the vmlinux_path (8 entries long) Using /boot/vmlinux for symbols Open Debuginfo file: /boot/vmlinux Try to find probe point from debuginfo. Matched function: do_open [2d0c7d6] Probe point found: do_open+0 Matched function: do_open [35d76b3] found inline addr: 0xc0000000004ba9e4 Failed to find "do_open%return", because do_open is an inlined function and has no return point. An error occurred in debuginfo analysis (-22). Trying to use symbols. Opening /sys/kernel/debug/tracing//README write=0 Opening /sys/kernel/debug/tracing//kprobe_events write=1 Writing event: r:probe/do_open _text+4469808 Writing event: r:probe/do_open_1 _text+4956344 Added new events: probe:do_open (on do_open%return) probe:do_open_1 (on do_open%return) You can now use it in all perf tools, such as: perf record -e probe:do_open_1 -aR sleep 1 naveen@ubuntu:~/linux/tools/perf$ sudo cat /sys/kernel/debug/kprobes/list c000000000041370 k kretprobe_trampoline+0x0 [OPTIMIZED] c0000000004ba0b8 r do_open+0x8 [DISABLED] c000000000443430 r do_open+0x0 [DISABLED] Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/d8cd1ef420ec22e3643ac332fdabcffc77319a42.1488961018.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-03-03kretprobes: Ensure probe location is at function entryNaveen N. Rao
kretprobes can be registered by specifying an absolute address or by specifying offset to a symbol. However, we need to ensure this falls at function entry so as to be able to determine the return address. Validate the same during kretprobe registration. By default, there should not be any offset from a function entry, as determined through a kallsyms_lookup(). Introduce arch_function_offset_within_entry() as a way for architectures to override this. Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/f1583bc4839a3862cfc2acefcc56f9c8837fa2ba.1487770934.git.naveen.n.rao@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2017-02-27kprobes: move kprobe declarations to asm-generic/kprobes.hLuis R. Rodriguez
Often all is needed is these small helpers, instead of compiler.h or a full kprobes.h. This is important for asm helpers, in fact even some asm/kprobes.h make use of these helpers... instead just keep a generic asm file with helpers useful for asm code with the least amount of clutter as possible. Likewise we need now to also address what to do about this file for both when architectures have CONFIG_HAVE_KPROBES, and when they do not. Then for when architectures have CONFIG_HAVE_KPROBES but have disabled CONFIG_KPROBES. Right now most asm/kprobes.h do not have guards against CONFIG_KPROBES, this means most architecture code cannot include asm/kprobes.h safely. Correct this and add guards for architectures missing them. Additionally provide architectures that not have kprobes support with the default asm-generic solution. This lets us force asm/kprobes.h on the header include/linux/kprobes.h always, but most importantly we can now safely include just asm/kprobes.h on architecture code without bringing the full kitchen sink of header files. Two architectures already provided a guard against CONFIG_KPROBES on its kprobes.h: sh, arch. The rest of the architectures needed gaurds added. We avoid including any not-needed headers on asm/kprobes.h unless kprobes have been enabled. In a subsequent atomic change we can try now to remove compiler.h from include/linux/kprobes.h. During this sweep I've also identified a few architectures defining a common macro needed for both kprobes and ftrace, that of the definition of the breakput instruction up. Some refer to this as BREAKPOINT_INSTRUCTION. This must be kept outside of the #ifdef CONFIG_KPROBES guard. [mcgrof@kernel.org: fix arm64 build] Link: http://lkml.kernel.org/r/CAB=NE6X1WMByuARS4mZ1g9+W=LuVBnMDnh_5zyN0CLADaVh=Jw@mail.gmail.com [sfr@canb.auug.org.au: fixup for kprobes declarations moving] Link: http://lkml.kernel.org/r/20170214165933.13ebd4f4@canb.auug.org.au Link: http://lkml.kernel.org/r/20170203233139.32682-1-mcgrof@kernel.org Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-01-14kprobes, extable: Identify kprobes trampolines as kernel text areaMasami Hiramatsu
Improve __kernel_text_address()/kernel_text_address() to return true if the given address is on a kprobe's instruction slot trampoline. This can help stacktraces to determine the address is on a text area or not. To implement this atomically in is_kprobe_*_slot(), also change the insn_cache page list to an RCU list. This changes timings a bit (it delays page freeing to the RCU garbage collection phase), but none of that is in the hot path. Note: this change can add small overhead to stack unwinders because it adds 2 additional checks to __kernel_text_address(). However, the impact should be very small, because kprobe_insn_pages list has 1 entry per 256 probes(on x86, on arm/arm64 it will be 1024 probes), and kprobe_optinsn_pages has 1 entry per 32 probes(on x86). In most use cases, the number of kprobe events may be less than 20, which means that is_kprobe_*_slot() will check just one entry. Tested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/148388747896.6869.6354262871751682264.stgit@devbox [ Improved the changelog and coding style. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-04perf/x86/hw_breakpoints: Disallow kernel breakpoints unless kprobe-safeAndy Lutomirski
Code on the kprobe blacklist doesn't want unexpected int3 exceptions. It probably doesn't want unexpected debug exceptions either. Be safe: disallow breakpoints in nokprobes code. On non-CONFIG_KPROBES kernels, there is no kprobe blacklist. In that case, disallow kernel breakpoints entirely. It will be particularly important to keep hw breakpoints out of the entry and NMI code once we move debug exceptions off the IST stack. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e14b152af99640448d895e3c2a8c2d5ee19a1325.1438312874.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-01-13kprobes: Pass the original kprobe for preparing optimized kprobeMasami Hiramatsu
Pass the original kprobe for preparing an optimized kprobe arch-dep part, since for some architecture (e.g. ARM32) requires the information in original kprobe. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: Jon Medhurst <tixy@linaro.org>
2014-10-27kprobes: introduce weak arch_check_ftrace_location() helper functionHeiko Carstens
Introduce weak arch_check_ftrace_location() helper function which architectures can override in order to implement handling of kprobes on function tracer call sites on their own, without depending on common code or implementing the KPROBES_ON_FTRACE feature. Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-06-12Merge branch 'perf-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull more perf updates from Ingo Molnar: "A second round of perf updates: - wide reaching kprobes sanitization and robustization, with the hope of fixing all 'probe this function crashes the kernel' bugs, by Masami Hiramatsu. - uprobes updates from Oleg Nesterov: tmpfs support, corner case fixes and robustization work. - perf tooling updates and fixes from Jiri Olsa, Namhyung Ki, Arnaldo et al: * Add support to accumulate hist periods (Namhyung Kim) * various fixes, refactorings and enhancements" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (101 commits) perf: Differentiate exec() and non-exec() comm events perf: Fix perf_event_comm() vs. exec() assumption uprobes/x86: Rename arch_uprobe->def to ->defparam, minor comment updates perf/documentation: Add description for conditional branch filter perf/x86: Add conditional branch filtering support perf/tool: Add conditional branch filter 'cond' to perf record perf: Add new conditional branch filter 'PERF_SAMPLE_BRANCH_COND' uprobes: Teach copy_insn() to support tmpfs uprobes: Shift ->readpage check from __copy_insn() to uprobe_register() perf/x86: Use common PMU interrupt disabled code perf/ARM: Use common PMU interrupt disabled code perf: Disable sampled events if no PMU interrupt perf: Fix use after free in perf_remove_from_context() perf tools: Fix 'make help' message error perf record: Fix poll return value propagation perf tools: Move elide bool into perf_hpp_fmt struct perf tools: Remove elide setup for SORT_MODE__MEMORY mode perf tools: Fix "==" into "=" in ui_browser__warning assignment perf tools: Allow overriding sysfs and proc finding with env var perf tools: Consider header files outside perf directory in tags target ...
2014-05-05tracing: Replace __get_cpu_var uses with this_cpu_ptrChristoph Lameter
Replace uses of &__get_cpu_var for address calculation with this_cpu_ptr. Link: http://lkml.kernel.org/p/alpine.DEB.2.10.1404291415560.18364@gentwo.org Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2014-04-24kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklistMasami Hiramatsu
Introduce NOKPROBE_SYMBOL() macro which builds a kprobes blacklist at kernel build time. The usage of this macro is similar to EXPORT_SYMBOL(), placed after the function definition: NOKPROBE_SYMBOL(function); Since this macro will inhibit inlining of static/inline functions, this patch also introduces a nokprobe_inline macro for static/inline functions. In this case, we must use NOKPROBE_SYMBOL() for the inline function caller. When CONFIG_KPROBES=y, the macro stores the given function address in the "_kprobe_blacklist" section. Since the data structures are not fully initialized by the macro (because there is no "size" information), those are re-initialized at boot time by using kallsyms. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Alok Kataria <akataria@vmware.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christopher Li <sparse@chrisli.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: David S. Miller <davem@davemloft.net> Cc: Jan-Simon Möller <dl9pf@gmx.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-sparse@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Ingo Molnar <mingo@kernel.org>