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* tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not definedSteven Rostedt (VMware)2020-01-031-0/+5
| | | | | | | | | | | | | On some archs with some configurations, MCOUNT_INSN_SIZE is not defined, and this makes the stack tracer fail to compile. Just define it to zero in this case. Link: https://lore.kernel.org/r/202001020219.zvE3vsty%lkp@intel.com Cc: stable@vger.kernel.org Fixes: 4df297129f622 ("tracing: Remove most or all of stack tracer stack size from stack_max_size") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Add locked_down checks to the open calls of files created for tracefsSteven Rostedt (VMware)2019-10-131-0/+8
| | | | | | | | | | | | | | | | Added various checks on open tracefs calls to see if tracefs is in lockdown mode, and if so, to return -EPERM. Note, the event format files (which are basically standard on all machines) as well as the enabled_functions file (which shows what is currently being traced) are not lockde down. Perhaps they should be, but it seems counter intuitive to lockdown information to help you know if the system has been modified. Link: http://lkml.kernel.org/r/CAHk-=wj7fGPKUspr579Cii-w_y60PtRaiDgKuxVtBAMK0VNNkA@mail.gmail.com Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Document the stack trace algorithm in the commentsSteven Rostedt (VMware)2019-08-311-0/+98
| | | | | | | | | | | As the max stack tracer algorithm is not that easy to understand from the code, add comments that explain the algorithm and mentions how ARCH_FTRACE_SHIFT_STACK_TRACER affects it. Link: http://lkml.kernel.org/r/20190806123455.487ac02b@gandalf.local.home Suggested-by: Joel Fernandes <joel@joelfernandes.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing/arm64: Have max stack tracer handle the case of return address after ↵Steven Rostedt (VMware)2019-08-311-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | data Most archs (well at least x86) store the function call return address on the stack before storing the local variables for the function. The max stack tracer depends on this in its algorithm to display the stack size of each function it finds in the back trace. Some archs (arm64), may store the return address (from its link register) just before calling a nested function. There's no reason to save the link register on leaf functions, as it wont be updated. This breaks the algorithm of the max stack tracer. Add a new define ARCH_FTRACE_SHIFT_STACK_TRACER that an architecture may set if it stores the return address (link register) after it stores the function's local variables, and have the stack trace shift the values of the mapped stack size to the appropriate functions. Link: 20190802094103.163576-1-jiping.ma2@windriver.com Reported-by: Jiping Ma <jiping.ma2@windriver.com> Acked-by: Will Deacon <will@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Remove the last struct stack_trace usageThomas Gleixner2019-04-291-21/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Simplify the stack retrieval code by using the storage array based interface. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094803.340000461@linutronix.de
* tracing: Cleanup stack trace codeThomas Gleixner2019-04-291-29/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Remove the extra array member of stack_dump_trace[] along with the ARRAY_SIZE - 1 initialization for struct stack_trace :: max_entries. Both are historical leftovers of no value. The stack tracer never exceeds the array and there is no extra storage requirement either. - Make variables which are only used in trace_stack.c static. - Simplify the enable/disable logic. - Rename stack_trace_print() as it's using the stack_trace_ namespace. Free the name up for stack trace related functions. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Alexander Potapenko <glider@google.com> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: linux-mm@kvack.org Cc: David Rientjes <rientjes@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: kasan-dev@googlegroups.com Cc: Mike Rapoport <rppt@linux.vnet.ibm.com> Cc: Akinobu Mita <akinobu.mita@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: iommu@lists.linux-foundation.org Cc: Robin Murphy <robin.murphy@arm.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: David Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Cc: linux-btrfs@vger.kernel.org Cc: dm-devel@redhat.com Cc: Mike Snitzer <snitzer@redhat.com> Cc: Alasdair Kergon <agk@redhat.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: intel-gfx@lists.freedesktop.org Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: David Airlie <airlied@linux.ie> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: linux-arch@vger.kernel.org Link: https://lkml.kernel.org/r/20190425094801.230654524@linutronix.de
* tracing: Remove the ULONG_MAX stack trace hackeryThomas Gleixner2019-04-141-15/+5
| | | | | | | | | | | | | | | | | | | No architecture terminates the stack trace with ULONG_MAX anymore. As the code checks the number of entries stored anyway there is no point in keeping all that ULONG_MAX magic around. The histogram code zeroes the storage before saving the stack, so if the trace is shorter than the maximum number of entries it can terminate the print loop if a zero entry is detected. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Potapenko <glider@google.com> Link: https://lkml.kernel.org/r/20190410103645.048761764@linutronix.de
* tracing: Use the return of str_has_prefix() to remove open coded numbersSteven Rostedt (VMware)2018-12-231-2/+4
| | | | | | | | | | | | | | There are several locations that compare constants to the beginning of string variables to determine what commands should be done, then the constant length is used to index into the string. This is error prone as the hard coded numbers have to match the size of the constants. Instead, use the len returned from str_has_prefix() and remove the open coded string length sizes. Cc: Joe Perches <joe@perches.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> (for trace_probe part) Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Use str_has_prefix() instead of using fixed sizesSteven Rostedt (VMware)2018-12-231-1/+1
| | | | | | | | | There are several instances of strncmp(str, "const", 123), where 123 is the strlen of the const string to check if "const" is the prefix of str. But this can be error prone. Use str_has_prefix() instead. Acked-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Have trace_stack nr_entries compare not be so subtleDan Carpenter2018-12-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dan Carpenter reviewed the trace_stack.c code and figured he found an off by one bug. "From reviewing the code, it seems possible for stack_trace_max.nr_entries to be set to .max_entries and in that case we would be reading one element beyond the end of the stack_dump_trace[] array. If it's not set to .max_entries then the bug doesn't affect runtime." Although it looks to be the case, it is not. Because we have: static unsigned long stack_dump_trace[STACK_TRACE_ENTRIES+1] = { [0 ... (STACK_TRACE_ENTRIES)] = ULONG_MAX }; struct stack_trace stack_trace_max = { .max_entries = STACK_TRACE_ENTRIES - 1, .entries = &stack_dump_trace[0], }; And: stack_trace_max.nr_entries = x; for (; x < i; x++) stack_dump_trace[x] = ULONG_MAX; Even if nr_entries equals max_entries, indexing with it into the stack_dump_trace[] array will not overflow the array. But if it is the case, the second part of the conditional that tests stack_dump_trace[nr_entries] to ULONG_MAX will always be true. By applying Dan's patch, it removes the subtle aspect of it and makes the if conditional slightly more efficient. Link: http://lkml.kernel.org/r/20180620110758.crunhd5bfep7zuiz@kili.mountain Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Have stack tracer trace full stackSteven Rostedt (VMware)2018-10-271-1/+1
| | | | | | | | | | | | | | | The stack tracer traces every function call checking the current stack (in non interrupt context), looking for the deepest stack, and saving it when it finds a new max depth. The problem is that it calls save_stack_trace(), and with the new ORC unwinder, it can skip too much. As it looks at the ip of the function call in the backtrace to find where it should start, it doesn't need to skip anything. The stack trace selftest would fail when the kernel was complied with the ORC UNDWINDER enabled. Without skipping functions when doing the stack trace, it now passes again. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Fix the file mode of stack tracerZhengyuan Liu2018-05-031-1/+1
| | | | | | | | | | It looks weird that the stack_trace_filter file can be written by root but shows that it does not have write permission by ll command. Link: http://lkml.kernel.org/r/1518054113-28096-1-git-send-email-liuzhengyuan@kylinos.cn Signed-off-by: Zhengyuan Liu <liuzhengyuan@kylinos.cn> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Have stack trace not record if RCU is not watchingSteven Rostedt (VMware)2017-12-151-0/+4
| | | | | | | | | | | | | | The stack tracer records a stack dump whenever it sees a stack usage that is more than what it ever saw before. This can happen at any function that is being traced. If it happens when the CPU is going idle (or other strange locations), RCU may not be watching, and in this case, the recording of the stack trace will trigger a warning. There's been lots of efforts to make hacks to allow stack tracing to proceed even if RCU is not watching, but this only causes more issues to appear. Simply do not trace a stack if RCU is not watching. It probably isn't a bad stack anyway. Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* Merge branch 'linus' into locking/core, to resolve conflictsIngo Molnar2017-11-071-0/+1
|\ | | | | | | | | | | | | | | | | | | Conflicts: include/linux/compiler-clang.h include/linux/compiler-gcc.h include/linux/compiler-intel.h include/uapi/linux/stddef.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman2017-11-021-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | locking/atomics: COCCINELLE/treewide: Convert trivial ACCESS_ONCE() patterns ↵Mark Rutland2017-10-251-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | to READ_ONCE()/WRITE_ONCE() Please do not apply this to mainline directly, instead please re-run the coccinelle script shown below and apply its output. For several reasons, it is desirable to use {READ,WRITE}_ONCE() in preference to ACCESS_ONCE(), and new code is expected to use one of the former. So far, there's been no reason to change most existing uses of ACCESS_ONCE(), as these aren't harmful, and changing them results in churn. However, for some features, the read/write distinction is critical to correct operation. To distinguish these cases, separate read/write accessors must be used. This patch migrates (most) remaining ACCESS_ONCE() instances to {READ,WRITE}_ONCE(), using the following coccinelle script: ---- // Convert trivial ACCESS_ONCE() uses to equivalent READ_ONCE() and // WRITE_ONCE() // $ make coccicheck COCCI=/home/mark/once.cocci SPFLAGS="--include-headers" MODE=patch virtual patch @ depends on patch @ expression E1, E2; @@ - ACCESS_ONCE(E1) = E2 + WRITE_ONCE(E1, E2) @ depends on patch @ expression E; @@ - ACCESS_ONCE(E) + READ_ONCE(E) ---- Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: davem@davemloft.net Cc: linux-arch@vger.kernel.org Cc: mpe@ellerman.id.au Cc: shuah@kernel.org Cc: snitzer@redhat.com Cc: thor.thayer@linux.intel.com Cc: tj@kernel.org Cc: viro@zeniv.linux.org.uk Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1508792849-3115-19-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tracing: Remove RCU work arounds from stack tracerSteven Rostedt (VMware)2017-09-231-15/+0
| | | | | | | | | | | | | | | | | Currently the stack tracer calls rcu_irq_enter() to make sure RCU is watching when it records a stack trace. But if the stack tracer is triggered while tracing inside of a rcu_irq_enter(), calling rcu_irq_enter() unconditionally can be problematic. The reason for having rcu_irq_enter() in the first place has been fixed from within the saving of the stack trace code, and there's no reason for doing it in the stack tracer itself. Just remove it. Cc: stable@vger.kernel.org Fixes: 0be964be0 ("module: Sanitize RCU usage and locking") Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Suggested-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Do note expose stack_trace_filter without DYNAMIC_FTRACESteven Rostedt (VMware)2017-07-121-0/+6
| | | | | | | | | | | | | The "stack_trace_filter" file only makes sense if DYNAMIC_FTRACE is configured in. If it is not, then the user can not filter any functions. Not only that, the open function causes warnings when DYNAMIC_FTRACE is not set. Link: http://lkml.kernel.org/r/20170710110521.600806-1-arnd@arndb.de Reported-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* ftrace: Fix regression with module command in stack_trace_filterSteven Rostedt (VMware)2017-06-291-2/+4
| | | | | | | | | | | | | | | | | | When doing the following command: # echo ":mod:kvm_intel" > /sys/kernel/tracing/stack_trace_filter it triggered a crash. This happened with the clean up of probes. It required all callers to the regex function (doing ftrace filtering) to have ops->private be a pointer to a trace_array. But for the stack tracer, that is not the case. Allow for the ops->private to be NULL, and change the function command callbacks to handle the trace_array pointer being NULL as well. Fixes: d2afd57a4b96 ("tracing/ftrace: Allow instances to have their own function probes") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* rcu/tracing: Add rcu_disabled to denote when rcu_irq_enter() will not workSteven Rostedt (VMware)2017-04-101-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tracing uses rcu_irq_enter() as a way to make sure that RCU is watching when it needs to use rcu_read_lock() and friends. This is because tracing can happen as RCU is about to enter user space, or about to go idle, and RCU does not watch for RCU read side critical sections as it makes the transition. There is a small location within the RCU infrastructure that rcu_irq_enter() itself will not work. If tracing were to occur in that section it will break if it tries to use rcu_irq_enter(). Originally, this happens with the stack_tracer, because it will call save_stack_trace when it encounters stack usage that is greater than any stack usage it had encountered previously. There was a case where that happened in the RCU section where rcu_irq_enter() did not work, and lockdep complained loudly about it. To fix it, stack tracing added a call to be disabled and RCU would disable stack tracing during the critical section that rcu_irq_enter() was inoperable. This solution worked, but there are other cases that use rcu_irq_enter() and it would be a good idea to let RCU give a way to let others know that rcu_irq_enter() will not work. For example, in trace events. Another helpful aspect of this change is that it also moves the per cpu variable called in the RCU critical section into a cache locale along with other RCU per cpu variables used in that same location. I'm keeping the stack_trace_disable() code, as that still could be used in the future by places that really need to disable it. And since it's only a static inline, it wont take up any kernel text if it is not used. Link: http://lkml.kernel.org/r/20170405093207.404f8deb@gandalf.local.home Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Rename trace_active to disable_stack_tracer and inline its modificationSteven Rostedt (VMware)2017-04-101-41/+9
| | | | | | | | | In order to eliminate a function call, make "trace_active" into "disable_stack_tracer" and convert stack_tracer_disable() and friends into static inline functions. Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Add stack_tracer_disable/enable() functionsSteven Rostedt (VMware)2017-04-101-0/+32
| | | | | | | | | | | There are certain parts of the kernel that cannot let stack tracing proceed (namely in RCU), because the stack tracer uses RCU, and parts of RCU internals cannot handle having RCU read side locks taken. Add stack_tracer_disable() and stack_tracer_enable() functions to let RCU stop stack tracing on the current CPU when it is in those critical sections. Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* tracing: Replace the per_cpu() with __this_cpu*() in trace_stack.cSteven Rostedt (VMware)2017-04-101-16/+7
| | | | | | | | | | | The updates to the trace_active per cpu variable can be updated with the __this_cpu_*() functions as it only gets updated on the CPU that the variable is on. Thanks to Paul McKenney for suggesting __this_cpu_* instead of this_cpu_*. Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
* scripts/spelling.txt: add "overide" pattern and fix typo instancesMasahiro Yamada2017-03-101-1/+1
| | | | | | | | | | | | | | | | | Fix typos and add the following to the scripts/spelling.txt: overide||override While we are here, fix the doubled "address" in the touched line Documentation/devicetree/bindings/regulator/ti-abb-regulator.txt. Also, fix the comment block style in the touched hunks in drivers/media/dvb-frontends/drx39xyj/drx_driver.h. Link: http://lkml.kernel.org/r/1481573103-11329-21-git-send-email-yamada.masahiro@socionext.com Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/task_stack.h> We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/task_stack.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> 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>
* tracing, kasan: Silence Kasan warning in check_stack of stack_tracerYang Shi2016-02-191-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When enabling stack trace via "echo 1 > /proc/sys/kernel/stack_tracer_enabled", the below KASAN warning is triggered: BUG: KASAN: stack-out-of-bounds in check_stack+0x344/0x848 at addr ffffffc0689ebab8 Read of size 8 by task ksoftirqd/4/29 page:ffffffbdc3a27ac0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x0() page dumped because: kasan: bad access detected CPU: 4 PID: 29 Comm: ksoftirqd/4 Not tainted 4.5.0-rc1 #129 Hardware name: Freescale Layerscape 2085a RDB Board (DT) Call trace: [<ffffffc000091300>] dump_backtrace+0x0/0x3a0 [<ffffffc0000916c4>] show_stack+0x24/0x30 [<ffffffc0009bbd78>] dump_stack+0xd8/0x168 [<ffffffc000420bb0>] kasan_report_error+0x6a0/0x920 [<ffffffc000421688>] kasan_report+0x70/0xb8 [<ffffffc00041f7f0>] __asan_load8+0x60/0x78 [<ffffffc0002e05c4>] check_stack+0x344/0x848 [<ffffffc0002e0c8c>] stack_trace_call+0x1c4/0x370 [<ffffffc0002af558>] ftrace_ops_no_ops+0x2c0/0x590 [<ffffffc00009f25c>] ftrace_graph_call+0x0/0x14 [<ffffffc0000881bc>] fpsimd_thread_switch+0x24/0x1e8 [<ffffffc000089864>] __switch_to+0x34/0x218 [<ffffffc0011e089c>] __schedule+0x3ac/0x15b8 [<ffffffc0011e1f6c>] schedule+0x5c/0x178 [<ffffffc0001632a8>] smpboot_thread_fn+0x350/0x960 [<ffffffc00015b518>] kthread+0x1d8/0x2b0 [<ffffffc0000874d0>] ret_from_fork+0x10/0x40 Memory state around the buggy address: ffffffc0689eb980: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f4 f4 f4 ffffffc0689eba00: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 >ffffffc0689eba80: 00 00 f1 f1 f1 f1 00 f4 f4 f4 f3 f3 f3 f3 00 00 ^ ffffffc0689ebb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffffc0689ebb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 The stacker tracer traverses the whole kernel stack when saving the max stack trace. It may touch the stack red zones to cause the warning. So, just disable the instrumentation to silence the warning. Link: http://lkml.kernel.org/r/1455309960-18930-1-git-send-email-yang.shi@linaro.org Signed-off-by: Yang Shi <yang.shi@linaro.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/stacktrace: Show entire trace if passed in function not foundSteven Rostedt2016-01-291-0/+7
| | | | | | | | | | | | | | | | | | | When a max stack trace is discovered, the stack dump is saved. In order to not record the overhead of the stack tracer, the ip of the traced function is looked for within the dump. The trace is started from the location of that function. But if for some reason the ip is not found, the entire stack trace is then truncated. That's not very useful. Instead, print everything if the ip of the traced function is not found within the trace. This issue showed up on s390. Link: http://lkml.kernel.org/r/20160129102241.1b3c9c04@gandalf.local.home Fixes: 72ac426a5bb0 ("tracing: Clean up stack tracing and fix fentry updates") Cc: stable@vger.kernel.org # v4.3+ Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* Merge tag 'trace-v4.4' of ↵Linus Torvalds2015-11-061-43/+49
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracking updates from Steven Rostedt: "Most of the changes are clean ups and small fixes. Some of them have stable tags to them. I searched through my INBOX just as the merge window opened and found lots of patches to pull. I ran them through all my tests and they were in linux-next for a few days. Features added this release: ---------------------------- - Module globbing. You can now filter function tracing to several modules. # echo '*:mod:*snd*' > set_ftrace_filter (Dmitry Safonov) - Tracer specific options are now visible even when the tracer is not active. It was rather annoying that you can only see and modify tracer options after enabling the tracer. Now they are in the options/ directory even when the tracer is not active. Although they are still only visible when the tracer is active in the trace_options file. - Trace options are now per instance (although some of the tracer specific options are global) - New tracefs file: set_event_pid. If any pid is added to this file, then all events in the instance will filter out events that are not part of this pid. sched_switch and sched_wakeup events handle next and the wakee pids" * tag 'trace-v4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (68 commits) tracefs: Fix refcount imbalance in start_creating() tracing: Put back comma for empty fields in boot string parsing tracing: Apply tracer specific options from kernel command line. tracing: Add some documentation about set_event_pid ring_buffer: Remove unneeded smp_wmb() before wakeup of reader benchmark tracing: Allow dumping traces without tracking trace started cpus ring_buffer: Fix more races when terminating the producer in the benchmark ring_buffer: Do no not complete benchmark reader too early tracing: Remove redundant TP_ARGS redefining tracing: Rename max_stack_lock to stack_trace_max_lock tracing: Allow arch-specific stack tracer recordmcount: arm64: Replace the ignored mcount call into nop recordmcount: Fix endianness handling bug for nop_mcount tracepoints: Fix documentation of RCU lockdep checks tracing: ftrace_event_is_function() can return boolean tracing: is_legal_op() can return boolean ring-buffer: rb_event_is_commit() can return boolean ring-buffer: rb_per_cpu_empty() can return boolean ring_buffer: ring_buffer_empty{cpu}() can return boolean ring-buffer: rb_is_reader_page() can return boolean ...
| * tracing: Rename max_stack_lock to stack_trace_max_lockSteven Rostedt (Red Hat)2015-11-031-8/+8
| | | | | | | | | | | | | | | | Now that max_stack_lock is a global variable, it requires a naming convention that is unlikely to collide. Rename it to the same naming convention that the other stack_trace variables have. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Allow arch-specific stack tracerAKASHI Takahiro2015-11-031-37/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A stack frame may be used in a different way depending on cpu architecture. Thus it is not always appropriate to slurp the stack contents, as current check_stack() does, in order to calcurate a stack index (height) at a given function call. At least not on arm64. In addition, there is a possibility that we will mistakenly detect a stale stack frame which has not been overwritten. This patch makes check_stack() a weak function so as to later implement arch-specific version. Link: http://lkml.kernel.org/r/1446182741-31019-5-git-send-email-takahiro.akashi@linaro.org Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing: Do not allow stack_tracer to record stack in NMISteven Rostedt (Red Hat)2015-10-211-0/+4
| | | | | | | | | | | | | | | | | | | | | | The code in stack tracer should not be executed within an NMI as it grabs spinlocks and stack tracing an NMI gives the possibility of causing a deadlock. Although this is safe on x86_64, because it does not perform stack traces when the task struct stack is not in use (interrupts and NMIs), it may be an issue for NMIs on i386 and other archs that use the same stack as the NMI. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing: Have stack tracer force RCU to be watchingSteven Rostedt (Red Hat)2015-10-201-0/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The stack tracer was triggering the WARN_ON() in module.c: static void module_assert_mutex_or_preempt(void) { #ifdef CONFIG_LOCKDEP if (unlikely(!debug_locks)) return; WARN_ON(!rcu_read_lock_sched_held() && !lockdep_is_held(&module_mutex)); #endif } The reason is that the stack tracer traces all function calls, and some of those calls happen while exiting or entering user space and idle. Some of these functions are called after RCU had already stopped watching, as RCU does not watch userspace or idle CPUs. If a max stack is hit, then the save_stack_trace() is called, which will check module addresses and call module_assert_mutex_or_preempt(), and then trigger the warning. Sad part is, the warning itself will also do a stack trace and tigger the same warning. That probably should be fixed. The warning was added by 0be964be0d45 "module: Sanitize RCU usage and locking" but this bug has probably been around longer. But it's unlikely to cause much harm, but the new warning causes the system to lock up. Cc: stable@vger.kernel.org # 4.2+ Cc: Peter Zijlstra <peterz@infradead.org> Cc:"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Clean up stack tracing and fix fentry updatesSteven Rostedt (Red Hat)2015-07-211-45/+23
| | | | | | | | | | | | | | | | | | | | Akashi Takahiro was porting the stack tracer to arm64 and found some issues with it. One was that it repeats the top function, due to the stack frame added by the mcount caller and added by itself. This was added when fentry came in, and before fentry created its own stack frame. But x86's fentry now creates its own stack frame, and there's no need to insert the function again. This also cleans up the code a bit, where it doesn't need to do something special for fentry, and doesn't include insertion of a duplicate entry for the called function being traced. Link: http://lkml.kernel.org/r/55A646EE.6030402@linaro.org Some-suggestions-by: Jungseok Lee <jungseoklee85@gmail.com> Some-suggestions-by: Mark Rutland <mark.rutland@arm.com> Reported-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: remove use of seq_printf return valueJoe Perches2015-04-161-2/+2
| | | | | | | | | | | | | | | | | | The seq_printf return value, because it's frequently misused, will eventually be converted to void. See: commit 1f33c41c03da ("seq_file: Rename seq_overflow() to seq_has_overflowed() and make public") Miscellanea: o Remove unused return value from trace_lookup_stack Signed-off-by: Joe Perches <joe@perches.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tracing: Use IS_ERR() check for return value of tracing_init_dentry()Steven Rostedt (Red Hat)2015-01-221-1/+1
| | | | | | | | | tracing_init_dentry() will soon return NULL as a valid pointer for the top level tracing directroy. NULL can not be used as an error value. Instead, switch to ERR_PTR() and check the return status with IS_ERR(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Remove unneeded includes of debugfs.h and fs.hSteven Rostedt (Red Hat)2015-01-221-2/+0
| | | | | | | | | | The creation of tracing files and directories is for the most part encapsulated in helper functions in trace.c. Other files do not need to include debugfs.h or fs.h, as they may have needed to in the past. Remove them from the files that do not need them. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* sched: Add helper for task stack page overrun checkingAaron Tomlin2014-09-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This facility is used in a few places so let's introduce a helper function to improve code readability. Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: oleg@redhat.com Cc: riel@redhat.com Cc: prarit@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: mpe@ellerman.id.au Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-3-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* init/main.c: Give init_task a canaryAaron Tomlin2014-09-191-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Tasks get their end of stack set to STACK_END_MAGIC with the aim to catch stack overruns. Currently this feature does not apply to init_task. This patch removes this restriction. Note that a similar patch was posted by Prarit Bhargava some time ago but was never merged: http://marc.info/?l=linux-kernel&m=127144305403241&w=2 Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: aneesh.kumar@linux.vnet.ibm.com Cc: dzickus@redhat.com Cc: bmr@redhat.com Cc: jcastillo@redhat.com Cc: jgh@redhat.com Cc: minchan@kernel.org Cc: tglx@linutronix.de Cc: hannes@cmpxchg.org Cc: Alex Thorlton <athorlton@sgi.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Daeseok Youn <daeseok.youn@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Fabian Frederick <fabf@skynet.be> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Michael Opdenacker <michael.opdenacker@free-electrons.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1410527779-8133-2-git-send-email-atomlin@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tracing: Print max callstack on stacktrace bugMinchan Kim2014-06-021-4/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While I played with my own feature(ex, something on the way to reclaim), the kernel would easily oops. I guessed that the reason had to do with stack overflow and wanted to prove it. I discovered the stack tracer which proved to be very useful for me but the kernel would oops before my user program gather the information via "watch cat /sys/kernel/debug/tracing/stack_trace" so I couldn't get any message from that. What I needed was to have the stack tracer emit the kernel stack usage before it does the oops so I could find what was hogging the stack. This patch shows the callstack of max stack usage right before an oops so we can find a culprit. So, the result is as follows. [ 1116.522206] init: lightdm main process (1246) terminated with status 1 [ 1119.922916] init: failsafe-x main process (1272) terminated with status 1 [ 3887.728131] kworker/u24:1 (6637) used greatest stack depth: 256 bytes left [ 6397.629227] cc1 (9554) used greatest stack depth: 128 bytes left [ 7174.467392] Depth Size Location (47 entries) [ 7174.467392] ----- ---- -------- [ 7174.467785] 0) 7248 256 get_page_from_freelist+0xa7/0x920 [ 7174.468506] 1) 6992 352 __alloc_pages_nodemask+0x1cd/0xb20 [ 7174.469224] 2) 6640 8 alloc_pages_current+0x10f/0x1f0 [ 7174.469413] 3) 6632 168 new_slab+0x2c5/0x370 [ 7174.469413] 4) 6464 8 __slab_alloc+0x3a9/0x501 [ 7174.469413] 5) 6456 80 __kmalloc+0x1cb/0x200 [ 7174.469413] 6) 6376 376 vring_add_indirect+0x36/0x200 [ 7174.469413] 7) 6000 144 virtqueue_add_sgs+0x2e2/0x320 [ 7174.469413] 8) 5856 288 __virtblk_add_req+0xda/0x1b0 [ 7174.469413] 9) 5568 96 virtio_queue_rq+0xd3/0x1d0 [ 7174.469413] 10) 5472 128 __blk_mq_run_hw_queue+0x1ef/0x440 [ 7174.469413] 11) 5344 16 blk_mq_run_hw_queue+0x35/0x40 [ 7174.469413] 12) 5328 96 blk_mq_insert_requests+0xdb/0x160 [ 7174.469413] 13) 5232 112 blk_mq_flush_plug_list+0x12b/0x140 [ 7174.469413] 14) 5120 112 blk_flush_plug_list+0xc7/0x220 [ 7174.469413] 15) 5008 64 io_schedule_timeout+0x88/0x100 [ 7174.469413] 16) 4944 128 mempool_alloc+0x145/0x170 [ 7174.469413] 17) 4816 96 bio_alloc_bioset+0x10b/0x1d0 [ 7174.469413] 18) 4720 48 get_swap_bio+0x30/0x90 [ 7174.469413] 19) 4672 160 __swap_writepage+0x150/0x230 [ 7174.469413] 20) 4512 32 swap_writepage+0x42/0x90 [ 7174.469413] 21) 4480 320 shrink_page_list+0x676/0xa80 [ 7174.469413] 22) 4160 208 shrink_inactive_list+0x262/0x4e0 [ 7174.469413] 23) 3952 304 shrink_lruvec+0x3e1/0x6a0 [ 7174.469413] 24) 3648 80 shrink_zone+0x3f/0x110 [ 7174.469413] 25) 3568 128 do_try_to_free_pages+0x156/0x4c0 [ 7174.469413] 26) 3440 208 try_to_free_pages+0xf7/0x1e0 [ 7174.469413] 27) 3232 352 __alloc_pages_nodemask+0x783/0xb20 [ 7174.469413] 28) 2880 8 alloc_pages_current+0x10f/0x1f0 [ 7174.469413] 29) 2872 200 __page_cache_alloc+0x13f/0x160 [ 7174.469413] 30) 2672 80 find_or_create_page+0x4c/0xb0 [ 7174.469413] 31) 2592 80 ext4_mb_load_buddy+0x1e9/0x370 [ 7174.469413] 32) 2512 176 ext4_mb_regular_allocator+0x1b7/0x460 [ 7174.469413] 33) 2336 128 ext4_mb_new_blocks+0x458/0x5f0 [ 7174.469413] 34) 2208 256 ext4_ext_map_blocks+0x70b/0x1010 [ 7174.469413] 35) 1952 160 ext4_map_blocks+0x325/0x530 [ 7174.469413] 36) 1792 384 ext4_writepages+0x6d1/0xce0 [ 7174.469413] 37) 1408 16 do_writepages+0x23/0x40 [ 7174.469413] 38) 1392 96 __writeback_single_inode+0x45/0x2e0 [ 7174.469413] 39) 1296 176 writeback_sb_inodes+0x2ad/0x500 [ 7174.469413] 40) 1120 80 __writeback_inodes_wb+0x9e/0xd0 [ 7174.469413] 41) 1040 160 wb_writeback+0x29b/0x350 [ 7174.469413] 42) 880 208 bdi_writeback_workfn+0x11c/0x480 [ 7174.469413] 43) 672 144 process_one_work+0x1d2/0x570 [ 7174.469413] 44) 528 112 worker_thread+0x116/0x370 [ 7174.469413] 45) 416 240 kthread+0xf3/0x110 [ 7174.469413] 46) 176 176 ret_from_fork+0x7c/0xb0 [ 7174.469413] ------------[ cut here ]------------ [ 7174.469413] kernel BUG at kernel/trace/trace_stack.c:174! [ 7174.469413] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC [ 7174.469413] Dumping ftrace buffer: [ 7174.469413] (ftrace buffer empty) [ 7174.469413] Modules linked in: [ 7174.469413] CPU: 0 PID: 440 Comm: kworker/u24:0 Not tainted 3.14.0+ #212 [ 7174.469413] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 7174.469413] Workqueue: writeback bdi_writeback_workfn (flush-253:0) [ 7174.469413] task: ffff880034170000 ti: ffff880029518000 task.ti: ffff880029518000 [ 7174.469413] RIP: 0010:[<ffffffff8112336e>] [<ffffffff8112336e>] stack_trace_call+0x2de/0x340 [ 7174.469413] RSP: 0000:ffff880029518290 EFLAGS: 00010046 [ 7174.469413] RAX: 0000000000000030 RBX: 000000000000002f RCX: 0000000000000000 [ 7174.469413] RDX: 0000000000000000 RSI: 000000000000002f RDI: ffffffff810b7159 [ 7174.469413] RBP: ffff8800295182f0 R08: ffffffffffffffff R09: 0000000000000000 [ 7174.469413] R10: 0000000000000001 R11: 0000000000000001 R12: ffffffff82768dfc [ 7174.469413] R13: 000000000000f2e8 R14: ffff8800295182b8 R15: 00000000000000f8 [ 7174.469413] FS: 0000000000000000(0000) GS:ffff880037c00000(0000) knlGS:0000000000000000 [ 7174.469413] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 7174.469413] CR2: 00002acd0b994000 CR3: 0000000001c0b000 CR4: 00000000000006f0 [ 7174.469413] Stack: [ 7174.469413] 0000000000000000 ffffffff8114fdb7 0000000000000087 0000000000001c50 [ 7174.469413] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 7174.469413] 0000000000000002 ffff880034170000 ffff880034171028 0000000000000000 [ 7174.469413] Call Trace: [ 7174.469413] [<ffffffff8114fdb7>] ? get_page_from_freelist+0xa7/0x920 [ 7174.469413] [<ffffffff816eee3f>] ftrace_call+0x5/0x2f [ 7174.469413] [<ffffffff81165065>] ? next_zones_zonelist+0x5/0x70 [ 7174.469413] [<ffffffff810a23fa>] ? __bfs+0x11a/0x270 [ 7174.469413] [<ffffffff81165065>] ? next_zones_zonelist+0x5/0x70 [ 7174.469413] [<ffffffff8114fdb7>] ? get_page_from_freelist+0xa7/0x920 [ 7174.469413] [<ffffffff8119092f>] ? alloc_pages_current+0x10f/0x1f0 [ 7174.469413] [<ffffffff811507fd>] __alloc_pages_nodemask+0x1cd/0xb20 [ 7174.469413] [<ffffffff810a4de6>] ? check_irq_usage+0x96/0xe0 [ 7174.469413] [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f [ 7174.469413] [<ffffffff8119092f>] alloc_pages_current+0x10f/0x1f0 [ 7174.469413] [<ffffffff81199cd5>] ? new_slab+0x2c5/0x370 [ 7174.469413] [<ffffffff81199cd5>] new_slab+0x2c5/0x370 [ 7174.469413] [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f [ 7174.469413] [<ffffffff816db002>] __slab_alloc+0x3a9/0x501 [ 7174.469413] [<ffffffff8119af8b>] ? __kmalloc+0x1cb/0x200 [ 7174.469413] [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200 [ 7174.469413] [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200 [ 7174.469413] [<ffffffff8141dc46>] ? vring_add_indirect+0x36/0x200 [ 7174.469413] [<ffffffff8119af8b>] __kmalloc+0x1cb/0x200 [ 7174.469413] [<ffffffff8141de10>] ? vring_add_indirect+0x200/0x200 [ 7174.469413] [<ffffffff8141dc46>] vring_add_indirect+0x36/0x200 [ 7174.469413] [<ffffffff8141e402>] virtqueue_add_sgs+0x2e2/0x320 [ 7174.469413] [<ffffffff8148e35a>] __virtblk_add_req+0xda/0x1b0 [ 7174.469413] [<ffffffff8148e503>] virtio_queue_rq+0xd3/0x1d0 [ 7174.469413] [<ffffffff8134aa0f>] __blk_mq_run_hw_queue+0x1ef/0x440 [ 7174.469413] [<ffffffff8134b0d5>] blk_mq_run_hw_queue+0x35/0x40 [ 7174.469413] [<ffffffff8134b7bb>] blk_mq_insert_requests+0xdb/0x160 [ 7174.469413] [<ffffffff8134be5b>] blk_mq_flush_plug_list+0x12b/0x140 [ 7174.469413] [<ffffffff81342237>] blk_flush_plug_list+0xc7/0x220 [ 7174.469413] [<ffffffff816e60ef>] ? _raw_spin_unlock_irqrestore+0x3f/0x70 [ 7174.469413] [<ffffffff816e16e8>] io_schedule_timeout+0x88/0x100 [ 7174.469413] [<ffffffff816e1665>] ? io_schedule_timeout+0x5/0x100 [ 7174.469413] [<ffffffff81149415>] mempool_alloc+0x145/0x170 [ 7174.469413] [<ffffffff8109baf0>] ? __init_waitqueue_head+0x60/0x60 [ 7174.469413] [<ffffffff811e246b>] bio_alloc_bioset+0x10b/0x1d0 [ 7174.469413] [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [<ffffffff81184110>] get_swap_bio+0x30/0x90 [ 7174.469413] [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [<ffffffff81184660>] __swap_writepage+0x150/0x230 [ 7174.469413] [<ffffffff810ab405>] ? do_raw_spin_unlock+0x5/0xa0 [ 7174.469413] [<ffffffff81184230>] ? end_swap_bio_read+0xc0/0xc0 [ 7174.469413] [<ffffffff81184515>] ? __swap_writepage+0x5/0x230 [ 7174.469413] [<ffffffff81184782>] swap_writepage+0x42/0x90 [ 7174.469413] [<ffffffff8115ae96>] shrink_page_list+0x676/0xa80 [ 7174.469413] [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f [ 7174.469413] [<ffffffff8115b872>] shrink_inactive_list+0x262/0x4e0 [ 7174.469413] [<ffffffff8115c1c1>] shrink_lruvec+0x3e1/0x6a0 [ 7174.469413] [<ffffffff8115c4bf>] shrink_zone+0x3f/0x110 [ 7174.469413] [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f [ 7174.469413] [<ffffffff8115c9e6>] do_try_to_free_pages+0x156/0x4c0 [ 7174.469413] [<ffffffff8115cf47>] try_to_free_pages+0xf7/0x1e0 [ 7174.469413] [<ffffffff81150db3>] __alloc_pages_nodemask+0x783/0xb20 [ 7174.469413] [<ffffffff8119092f>] alloc_pages_current+0x10f/0x1f0 [ 7174.469413] [<ffffffff81145c0f>] ? __page_cache_alloc+0x13f/0x160 [ 7174.469413] [<ffffffff81145c0f>] __page_cache_alloc+0x13f/0x160 [ 7174.469413] [<ffffffff81146c6c>] find_or_create_page+0x4c/0xb0 [ 7174.469413] [<ffffffff811463e5>] ? find_get_page+0x5/0x130 [ 7174.469413] [<ffffffff812837b9>] ext4_mb_load_buddy+0x1e9/0x370 [ 7174.469413] [<ffffffff81284c07>] ext4_mb_regular_allocator+0x1b7/0x460 [ 7174.469413] [<ffffffff81281070>] ? ext4_mb_use_preallocated+0x40/0x360 [ 7174.469413] [<ffffffff816eee3f>] ? ftrace_call+0x5/0x2f [ 7174.469413] [<ffffffff81287eb8>] ext4_mb_new_blocks+0x458/0x5f0 [ 7174.469413] [<ffffffff8127d83b>] ext4_ext_map_blocks+0x70b/0x1010 [ 7174.469413] [<ffffffff8124e6d5>] ext4_map_blocks+0x325/0x530 [ 7174.469413] [<ffffffff81253871>] ext4_writepages+0x6d1/0xce0 [ 7174.469413] [<ffffffff812531a0>] ? ext4_journalled_write_end+0x330/0x330 [ 7174.469413] [<ffffffff811539b3>] do_writepages+0x23/0x40 [ 7174.469413] [<ffffffff811d2365>] __writeback_single_inode+0x45/0x2e0 [ 7174.469413] [<ffffffff811d36ed>] writeback_sb_inodes+0x2ad/0x500 [ 7174.469413] [<ffffffff811d39de>] __writeback_inodes_wb+0x9e/0xd0 [ 7174.469413] [<ffffffff811d40bb>] wb_writeback+0x29b/0x350 [ 7174.469413] [<ffffffff81057c3d>] ? __local_bh_enable_ip+0x6d/0xd0 [ 7174.469413] [<ffffffff811d6e9c>] bdi_writeback_workfn+0x11c/0x480 [ 7174.469413] [<ffffffff81070610>] ? process_one_work+0x170/0x570 [ 7174.469413] [<ffffffff81070672>] process_one_work+0x1d2/0x570 [ 7174.469413] [<ffffffff81070610>] ? process_one_work+0x170/0x570 [ 7174.469413] [<ffffffff81071bb6>] worker_thread+0x116/0x370 [ 7174.469413] [<ffffffff81071aa0>] ? manage_workers.isra.19+0x2e0/0x2e0 [ 7174.469413] [<ffffffff81078e53>] kthread+0xf3/0x110 [ 7174.469413] [<ffffffff81078d60>] ? flush_kthread_worker+0x150/0x150 [ 7174.469413] [<ffffffff816ef0ec>] ret_from_fork+0x7c/0xb0 [ 7174.469413] [<ffffffff81078d60>] ? flush_kthread_worker+0x150/0x150 [ 7174.469413] Code: c0 49 bc fc 8d 76 82 ff ff ff ff e8 44 5a 5b 00 31 f6 8b 05 95 2b b3 00 48 39 c6 7d 0e 4c 8b 04 f5 20 5f c5 81 49 83 f8 ff 75 11 <0f> 0b 48 63 05 71 5a 64 01 48 29 c3 e9 d0 fd ff ff 48 8d 5e 01 [ 7174.469413] RIP [<ffffffff8112336e>] stack_trace_call+0x2de/0x340 [ 7174.469413] RSP <ffff880029518290> [ 7174.469413] ---[ end trace c97d325b36b718f3 ]--- Link: http://lkml.kernel.org/p/1401683592-1651-1-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_funcJiaxing Wang2014-04-241-2/+6
| | | | | | | | | | | | | | | | | | | | | | When using ftrace_ops_list_func, we should skip 4 instead of 3, to avoid ftrace_call+0x5/0xb appearing in the stack trace: Depth Size Location (110 entries) ----- ---- -------- 0) 2956 0 update_curr+0xe/0x1e0 1) 2956 68 ftrace_call+0x5/0xb 2) 2888 92 enqueue_entity+0x53/0xe80 3) 2796 80 enqueue_task_fair+0x47/0x7e0 4) 2716 28 enqueue_task+0x45/0x70 5) 2688 12 activate_task+0x22/0x30 Add a function using_ftrace_ops_list_func() to test for this while keeping ftrace_ops_list_func to remain static. Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cn Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Add BUG_ON when stack end location is over writtenAaron Tomlin2014-03-241-0/+3
| | | | | | | | | | | | | | | | | | | | | It is difficult to detect a stack overrun when it actually occurs. We have observed that this type of corruption is often silent and can go unnoticed. Once the corrupted region is examined, the outcome is undefined and often results in sporadic system crashes. When the stack tracing feature is enabled, let's check for this condition and take appropriate action. Note: init_task doesn't get its stack end location set to STACK_END_MAGIC. Link: http://lkml.kernel.org/r/1395669837-30209-1-git-send-email-atomlin@redhat.com Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Add generic tracing_lseek() functionSteven Rostedt (Red Hat)2014-01-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | Trace event triggers added a lseek that uses the ftrace_filter_lseek() function. Unfortunately, when function tracing is not configured in that function is not defined and the kernel fails to build. This is the second time that function was added to a file ops and it broke the build due to requiring special config dependencies. Make a generic tracing_lseek() that all the tracing utilities may use. Also, modify the old ftrace_filter_lseek() to return 0 instead of 1 on WRONLY. Not sure why it was a 1 as that does not make sense. This also changes the old tracing_seek() to modify the file pos pointer on WRONLY as well. Reported-by: kbuild test robot <fengguang.wu@intel.com> Tested-by: Tom Zanussi <tom.zanussi@linux.intel.com> Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* Merge tag 'trace-3.10' of ↵Linus Torvalds2013-04-291-7/+69
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace Pull tracing updates from Steven Rostedt: "Along with the usual minor fixes and clean ups there are a few major changes with this pull request. 1) Multiple buffers for the ftrace facility This feature has been requested by many people over the last few years. I even heard that Google was about to implement it themselves. I finally had time and cleaned up the code such that you can now create multiple instances of the ftrace buffer and have different events go to different buffers. This way, a low frequency event will not be lost in the noise of a high frequency event. Note, currently only events can go to different buffers, the tracers (ie function, function_graph and the latency tracers) still can only be written to the main buffer. 2) The function tracer triggers have now been extended. The function tracer had two triggers. One to enable tracing when a function is hit, and one to disable tracing. Now you can record a stack trace on a single (or many) function(s), take a snapshot of the buffer (copy it to the snapshot buffer), and you can enable or disable an event to be traced when a function is hit. 3) A perf clock has been added. A "perf" clock can be chosen to be used when tracing. This will cause ftrace to use the same clock as perf uses, and hopefully this will make it easier to interleave the perf and ftrace data for analysis." * tag 'trace-3.10' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (82 commits) tracepoints: Prevent null probe from being added tracing: Compare to 1 instead of zero for is_signed_type() tracing: Remove obsolete macro guard _TRACE_PROFILE_INIT ftrace: Get rid of ftrace_profile_bits tracing: Check return value of tracing_init_dentry() tracing: Get rid of unneeded key calculation in ftrace_hash_move() tracing: Reset ftrace_graph_filter_enabled if count is zero tracing: Fix off-by-one on allocating stat->pages kernel: tracing: Use strlcpy instead of strncpy tracing: Update debugfs README file tracing: Fix ftrace_dump() tracing: Rename trace_event_mutex to trace_event_sem tracing: Fix comment about prefix in arch_syscall_match_sym_name() tracing: Convert trace_destroy_fields() to static tracing: Move find_event_field() into trace_events.c tracing: Use TRACE_MAX_PRINT instead of constant tracing: Use pr_warn_once instead of open coded implementation ring-buffer: Add ring buffer startup selftest tracing: Bring Documentation/trace/ftrace.txt up to date tracing: Add "perf" trace_clock ... Conflicts: kernel/trace/ftrace.c kernel/trace/trace.c
| * tracing: Check return value of tracing_init_dentry()Namhyung Kim2013-04-131-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | Check return value and bail out if it's NULL. Link: http://lkml.kernel.org/r/1365553093-10180-2-git-send-email-namhyung@kernel.org Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: stable@vger.kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Remove most or all of stack tracer stack size from stack_max_sizeSteven Rostedt (Red Hat)2013-03-151-21/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the depth reported in the stack tracer stack_trace file does not match the stack_max_size file. This is because the stack_max_size includes the overhead of stack tracer itself while the depth does not. The first time a max is triggered, a calculation is not performed that figures out the overhead of the stack tracer and subtracts it from the stack_max_size variable. The overhead is stored and is subtracted from the reported stack size for comparing for a new max. Now the stack_max_size corresponds to the reported depth: # cat stack_max_size 4640 # cat stack_trace Depth Size Location (48 entries) ----- ---- -------- 0) 4640 32 _raw_spin_lock+0x18/0x24 1) 4608 112 ____cache_alloc+0xb7/0x22d 2) 4496 80 kmem_cache_alloc+0x63/0x12f 3) 4416 16 mempool_alloc_slab+0x15/0x17 [...] While testing against and older gcc on x86 that uses mcount instead of fentry, I found that pasing in ip + MCOUNT_INSN_SIZE let the stack trace show one more function deep which was missing before. Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Fix stack tracer with fentry useSteven Rostedt (Red Hat)2013-03-151-4/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When gcc 4.6 on x86 is used, the function tracer will use the new option -mfentry which does a call to "fentry" at every function instead of "mcount". The significance of this is that fentry is called as the first operation of the function instead of the mcount usage of being called after the stack. This causes the stack tracer to show some bogus results for the size of the last function traced, as well as showing "ftrace_call" instead of the function. This is due to the stack frame not being set up by the function that is about to be traced. # cat stack_trace Depth Size Location (48 entries) ----- ---- -------- 0) 4824 216 ftrace_call+0x5/0x2f 1) 4608 112 ____cache_alloc+0xb7/0x22d 2) 4496 80 kmem_cache_alloc+0x63/0x12f The 216 size for ftrace_call includes both the ftrace_call stack (which includes the saving of registers it does), as well as the stack size of the parent. To fix this, if CC_USING_FENTRY is defined, then the stack_tracer will reserve the first item in stack_dump_trace[] array when calling save_stack_trace(), and it will fill it in with the parent ip. Then the code will look for the parent pointer on the stack and give the real size of the parent's stack pointer: # cat stack_trace Depth Size Location (14 entries) ----- ---- -------- 0) 2640 48 update_group_power+0x26/0x187 1) 2592 224 update_sd_lb_stats+0x2a5/0x4ac 2) 2368 160 find_busiest_group+0x31/0x1f1 3) 2208 256 load_balance+0xd9/0x662 I'm Cc'ing stable, although it's not urgent, as it only shows bogus size for item #0, the rest of the trace is legit. It should still be corrected in previous stable releases. Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
| * tracing: Use stack of calling function for stack tracerSteven Rostedt (Red Hat)2013-03-151-5/+7
| | | | | | | | | | | | | | | | | | | | | | Use the stack of stack_trace_call() instead of check_stack() as the test pointer for max stack size. It makes it a bit cleaner and a little more accurate. Adding stable, as a later fix depends on this patch. Cc: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | tracing: Fix possible NULL pointer dereferencesNamhyung Kim2013-04-121-1/+1
|/ | | | | | | | | | | | | | | | | | | | | | | | Currently set_ftrace_pid and set_graph_function files use seq_lseek for their fops. However seq_open() is called only for FMODE_READ in the fops->open() so that if an user tries to seek one of those file when she open it for writing, it sees NULL seq_file and then panic. It can be easily reproduced with following command: $ cd /sys/kernel/debug/tracing $ echo 1234 | sudo tee -a set_ftrace_pid In this example, GNU coreutils' tee opens the file with fopen(, "a") and then the fopen() internally calls lseek(). Link: http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: stable@vger.kernel.org Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* tracing: Remove unneeded checks from the stack tracerAnton Vorontsov2012-11-191-4/+0
| | | | | | | | | | | | | | | | | It seems that 'ftrace_enabled' flag should not be used inside the tracer functions. The ftrace core is using this flag for internal purposes, and the flag wasn't meant to be used in tracers' runtime checks. stack tracer is the only tracer that abusing the flag. So stop it from serving as a bad example. Also, there is a local 'stack_trace_disabled' flag in the stack tracer, which is never updated; so it can be removed as well. Link: http://lkml.kernel.org/r/1342637761-9655-1-git-send-email-anton.vorontsov@linaro.org Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* ftrace: Add default recursion protection for function tracingSteven Rostedt2012-07-311-0/+1
| | | | | | | | | | | | | | | | | | As more users of the function tracer utility are being added, they do not always add the necessary recursion protection. To protect from function recursion due to tracing, if the callback ftrace_ops does not specifically specify that it protects against recursion (by setting the FTRACE_OPS_FL_RECURSION_SAFE flag), the list operation will be called by the mcount trampoline which adds recursion protection. If the flag is set, then the function will be called directly with no extra protection. Note, the list operation is called if more than one function callback is registered, or if the arch does not support all of the function tracer features. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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