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* x86/stacktrace: Do not fail for ORC with regs on stackJiri Slaby2018-06-211-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | save_stack_trace_reliable now returns "non reliable" when there are kernel pt_regs on stack. This means an interrupt or exception happened somewhere down the route. It is a problem for the frame pointer unwinder, because the frame might not have been set up yet when the irq happened, so the unwinder might fail to unwind from the interrupted function. With ORC, this is not a problem, as ORC has out-of-band data. We can find ORC data even for the IP in the interrupted function and always unwind one level up reliably. So lift the check to apply only when CONFIG_FRAME_POINTER=y is enabled. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/lkml/20180518064713.26440-4-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/stacktrace: Clarify the reliable success pathsJiri Slaby2018-06-211-4/+12
| | | | | | | | | | | | | | | | | | | | | | | Make clear which path is for user tasks and for kthreads and idle tasks. This will allow easier plug-in of the ORC unwinder in the next patches. Note that we added a check for unwind error to the top of the loop, so that an error is returned also for user tasks (the 'goto success' would skip the check after the loop otherwise). Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/lkml/20180518064713.26440-3-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/stacktrace: Remove STACKTRACE_DUMP_ONCEJiri Slaby2018-06-211-16/+2
| | | | | | | | | | | | | | | | | | | | | | | The stack unwinding can sometimes fail yet. Especially with the generated debug info. So do not yell at users -- live patching (the only user of this interface) will inform the user about the failure gracefully. And given this was the only user of the macro, remove the macro proper too. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/lkml/20180518064713.26440-2-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/stacktrace: Do not unwind after user regsJiri Slaby2018-06-211-9/+0
| | | | | | | | | | | | | | | | | | Josh pointed out, that there is no way a frame can be after user regs. So remove the last unwind and the check. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/lkml/20180518064713.26440-1-jslaby@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge branch 'x86-pti-for-linus' of ↵Linus Torvalds2018-01-031-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 page table isolation fixes from Thomas Gleixner: "A couple of urgent fixes for PTI: - Fix a PTE mismatch between user and kernel visible mapping of the cpu entry area (differs vs. the GLB bit) and causes a TLB mismatch MCE on older AMD K8 machines - Fix the misplaced CR3 switch in the SYSCALL compat entry code which causes access to unmapped kernel memory resulting in double faults. - Fix the section mismatch of the cpu_tss_rw percpu storage caused by using a different mechanism for declaration and definition. - Two fixes for dumpstack which help to decode entry stack issues better - Enable PTI by default in Kconfig. We should have done that earlier, but it slipped through the cracks. - Exclude AMD from the PTI enforcement. Not necessarily a fix, but if AMD is so confident that they are not affected, then we should not burden users with the overhead" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/process: Define cpu_tss_rw in same section as declaration x86/pti: Switch to kernel CR3 at early in entry_SYSCALL_compat() x86/dumpstack: Print registers for first stack frame x86/dumpstack: Fix partial register dumps x86/pti: Make sure the user/kernel PTEs match x86/cpu, x86/pti: Do not enable PTI on AMD processors x86/pti: Enable PTI by default
| * x86/dumpstack: Fix partial register dumpsJosh Poimboeuf2018-01-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The show_regs_safe() logic is wrong. When there's an iret stack frame, it prints the entire pt_regs -- most of which is random stack data -- instead of just the five registers at the end. show_regs_safe() is also poorly named: the on_stack() checks aren't for safety. Rename the function to show_regs_if_on_stack() and add a comment to explain why the checks are needed. These issues were introduced with the "partial register dump" feature of the following commit: b02fcf9ba121 ("x86/unwinder: Handle stack overflows more gracefully") That patch had gone through a few iterations of development, and the above issues were artifacts from a previous iteration of the patch where 'regs' pointed directly to the iret frame rather than to the (partially empty) pt_regs. Tested-by: Alexander Tsoy <alexander@tsoy.me> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toralf Förster <toralf.foerster@gmx.de> Cc: stable@vger.kernel.org Fixes: b02fcf9ba121 ("x86/unwinder: Handle stack overflows more gracefully") Link: http://lkml.kernel.org/r/5b05b8b344f59db2d3d50dbdeba92d60f2304c54.1514736742.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | x86/stacktrace: Make zombie stack traces reliableJosh Poimboeuf2017-12-191-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit: 1959a60182f4 ("x86/dumpstack: Pin the target stack when dumping it") changed the behavior of stack traces for zombies. Before that commit, /proc/<pid>/stack reported the last execution path of the zombie before it died: [<ffffffff8105b877>] do_exit+0x6f7/0xa80 [<ffffffff8105bc79>] do_group_exit+0x39/0xa0 [<ffffffff8105bcf0>] __wake_up_parent+0x0/0x30 [<ffffffff8152dd09>] system_call_fastpath+0x16/0x1b [<00007fd128f9c4f9>] 0x7fd128f9c4f9 [<ffffffffffffffff>] 0xffffffffffffffff After the commit, it just reports an empty stack trace. The new behavior is actually probably more correct. If the stack refcount has gone down to zero, then the task has already gone through do_exit() and isn't going to run anymore. The stack could be freed at any time and is basically gone, so reporting an empty stack makes sense. However, save_stack_trace_tsk_reliable() treats such a missing stack condition as an error. That can cause livepatch transition stalls if there are any unreaped zombies. Instead, just treat it as a reliable, empty stack. Reported-and-tested-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: live-patching@vger.kernel.org Fixes: af085d9084b4 ("stacktrace/x86: add function for detecting reliable stack traces") Link: http://lkml.kernel.org/r/e4b09e630e99d0c1080528f0821fc9d9dbaeea82.1513631620.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | x86/stacktrace: Avoid recording save_stack_trace() wrappersVlastimil Babka2017-09-291-3/+7
|/ | | | | | | | | | | | | | | | | | | | | | | | | | The save_stack_trace() and save_stack_trace_tsk() wrappers of __save_stack_trace() add themselves to the call stack, and thus appear in the recorded stacktraces. This is redundant and wasteful when we have limited space to record the useful part of the backtrace with e.g. page_owner functionality. Fix this by making sure __save_stack_trace() is noinline (which matches the current gcc decision) and bumping the skip in the wrappers (save_stack_trace_tsk() only when called for the current task). This is similar to what was done for arm in 3683f44c42e9 ("ARM: stacktrace: avoid listing stacktrace functions in stacktrace") and is pending for arm64. Also make sure that __save_stack_trace_reliable() doesn't get this problem in the future by marking it __always_inline (which matches current gcc decision), per Josh Poimboeuf. Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20170929092335.2744-1-vbabka@suse.cz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* stacktrace/x86: add function for detecting reliable stack tracesJosh Poimboeuf2017-03-081-1/+95
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For live patching and possibly other use cases, a stack trace is only useful if it can be assured that it's completely reliable. Add a new save_stack_trace_tsk_reliable() function to achieve that. Note that if the target task isn't the current task, and the target task is allowed to run, then it could be writing the stack while the unwinder is reading it, resulting in possible corruption. So the caller of save_stack_trace_tsk_reliable() must ensure that the task is either 'current' or inactive. save_stack_trace_tsk_reliable() relies on the x86 unwinder's detection of pt_regs on the stack. If the pt_regs are not user-mode registers from a syscall, then they indicate an in-kernel interrupt or exception (e.g. preemption or a page fault), in which case the stack is considered unreliable due to the nature of frame pointers. It also relies on the x86 unwinder's detection of other issues, such as: - corrupted stack data - stack grows the wrong way - stack walk doesn't reach the bottom - user didn't provide a large enough entries array Such issues are reported by checking unwind_error() and !unwind_done(). Also add CONFIG_HAVE_RELIABLE_STACKTRACE so arch-independent code can determine at build time whether the function is implemented. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Ingo Molnar <mingo@kernel.org> # for the x86 changes Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* 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>
* sched/headers: Prepare for new header dependencies before moving code to ↵Ingo Molnar2017-03-021-0/+1
| | | | | | | | | | | | | | | | | | | | <linux/sched/debug.h> We are going to split <linux/sched/debug.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/debug.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>
* x86/stacktrace: Convert save_stack_trace_*() to use the new unwinderJosh Poimboeuf2016-09-201-45/+29
| | | | | | | | | | | | | | | | | | | | | | | Convert save_stack_trace_*() to use the new unwinder. dump_trace() has been deprecated. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.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/815494c627d89887db0ce56ceffd58ad16ee6c21.1474045023.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/dumpstack: Pin the target stack when dumping itAndy Lutomirski2016-09-161-0/+5
| | | | | | | | | | | | | | | | | | | | | Specifically, pin the stack in save_stack_trace_tsk() and show_trace_log_lvl(). This will prevent a crash if the target task dies before or while dumping its stack once we start freeing task stacks early. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jann Horn <jann@thejh.net> Cc: Josh Poimboeuf <jpoimboe@redhat.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/cf0082cde65d1941a996d026f2b2cdbfaca17bfa.1474003868.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/dumpstack: Add get_stack_info() interfaceJosh Poimboeuf2016-09-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | valid_stack_ptr() is buggy: it assumes that all stacks are of size THREAD_SIZE, which is not true for exception stacks. So the walk_stack() callbacks will need to know the location of the beginning of the stack as well as the end. Another issue is that in general the various features of a stack (type, size, next stack pointer, description string) are scattered around in various places throughout the stack dump code. Encapsulate all that information in a single place with a new stack_info struct and a get_stack_info() interface. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.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/8164dd0db96b7e6a279fa17ae5e6dc375eecb4a9.1473905218.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* x86/kernel: Audit and remove any unnecessary uses of module.hPaul Gortmaker2016-07-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Historically a lot of these existed because we did not have a distinction between what was modular code and what was providing support to modules via EXPORT_SYMBOL and friends. That changed when we forked out support for the latter into the export.h file. This means we should be able to reduce the usage of module.h in code that is obj-y Makefile or bool Kconfig. The advantage in doing so is that module.h itself sources about 15 other headers; adding significantly to what we feed cpp, and it can obscure what headers we are effectively using. Since module.h was the source for init.h (for __init) and for export.h (for EXPORT_SYMBOL) we consider each obj-y/bool instance for the presence of either and replace as needed. Build testing revealed some implicit header usage that was fixed up accordingly. Note that some bool/obj-y instances remain since module.h is the header for some exception table entry stuff, and for things like __init_or_module (code that is tossed when MODULES=n). Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.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/20160714001901.31603-4-paul.gortmaker@windriver.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* perf: generalize perf_callchainAlexei Starovoitov2016-02-201-7/+11
| | | | | | | | . avoid walking the stack when there is no room left in the buffer . generalize get_perf_callchain() to be called from bpf helper Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* x86: Swap save_stack_trace_regs parametersMasami Hiramatsu2011-06-141-1/+1
| | | | | | | | | | | | | Swap the 1st and 2nd parameters of save_stack_trace_regs() as same as the parameters of save_stack_trace_tsk(). Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Namhyung Kim <namhyung@gmail.com> Link: http://lkml.kernel.org/r/20110608070921.17777.31103.stgit@fedora15 Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* x86: Remove warning and warning_symbol from struct stacktrace_opsRichard Weinberger2011-05-121-13/+0
| | | | | | | | | | | | | | | | | | | Both warning and warning_symbol are nowhere used. Let's get rid of them. Signed-off-by: Richard Weinberger <richard@nod.at> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Huang Ying <ying.huang@intel.com> Cc: Soeren Sandmann Pedersen <ssp@redhat.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: x86 <x86@kernel.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Robert Richter <robert.richter@amd.com> Cc: Paul Mundt <lethal@linux-sh.org> Link: http://lkml.kernel.org/r/1305205872-10321-2-git-send-email-richard@nod.at Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86, dumpstack: Correct stack dump info when frame pointer is availableNamhyung Kim2011-03-181-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current stack dump code scans entire stack and check each entry contains a pointer to kernel code. If CONFIG_FRAME_POINTER=y it could mark whether the pointer is valid or not based on value of the frame pointer. Invalid entries could be preceded by '?' sign. However this was not going to happen because scan start point was always higher than the frame pointer so that they could not meet. Commit 9c0729dc8062 ("x86: Eliminate bp argument from the stack tracing routines") delayed bp acquisition point, so the bp was read in lower frame, thus all of the entries were marked invalid. This patch fixes this by reverting above commit while retaining stack_frame() helper as suggested by Frederic Weisbecker. End result looks like below: before: [ 3.508329] Call Trace: [ 3.508551] [<ffffffff814f35c9>] ? panic+0x91/0x199 [ 3.508662] [<ffffffff814f3739>] ? printk+0x68/0x6a [ 3.508770] [<ffffffff81a981b2>] ? mount_block_root+0x257/0x26e [ 3.508876] [<ffffffff81a9821f>] ? mount_root+0x56/0x5a [ 3.508975] [<ffffffff81a98393>] ? prepare_namespace+0x170/0x1a9 [ 3.509216] [<ffffffff81a9772b>] ? kernel_init+0x1d2/0x1e2 [ 3.509335] [<ffffffff81003894>] ? kernel_thread_helper+0x4/0x10 [ 3.509442] [<ffffffff814f6880>] ? restore_args+0x0/0x30 [ 3.509542] [<ffffffff81a97559>] ? kernel_init+0x0/0x1e2 [ 3.509641] [<ffffffff81003890>] ? kernel_thread_helper+0x0/0x10 after: [ 3.522991] Call Trace: [ 3.523351] [<ffffffff814f35b9>] panic+0x91/0x199 [ 3.523468] [<ffffffff814f3729>] ? printk+0x68/0x6a [ 3.523576] [<ffffffff81a981b2>] mount_block_root+0x257/0x26e [ 3.523681] [<ffffffff81a9821f>] mount_root+0x56/0x5a [ 3.523780] [<ffffffff81a98393>] prepare_namespace+0x170/0x1a9 [ 3.523885] [<ffffffff81a9772b>] kernel_init+0x1d2/0x1e2 [ 3.523987] [<ffffffff81003894>] kernel_thread_helper+0x4/0x10 [ 3.524228] [<ffffffff814f6880>] ? restore_args+0x0/0x30 [ 3.524345] [<ffffffff81a97559>] ? kernel_init+0x0/0x1e2 [ 3.524445] [<ffffffff81003890>] ? kernel_thread_helper+0x0/0x10 -v5: * fix build breakage with oprofile -v4: * use 0 instead of regs->bp * separate out printk changes -v3: * apply comment from Frederic * add a couple of printk fixes Signed-off-by: Namhyung Kim <namhyung@gmail.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Soren Sandmann <ssp@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Robert Richter <robert.richter@amd.com> LKML-Reference: <1300416006-3163-1-git-send-email-namhyung@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: Eliminate bp argument from the stack tracing routinesSoeren Sandmann Pedersen2010-11-181-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The various stack tracing routines take a 'bp' argument in which the caller is supposed to provide the base pointer to use, or 0 if doesn't have one. Since bp is garbage whenever CONFIG_FRAME_POINTER is not defined, this means all callers in principle should either always pass 0, or be conditional on CONFIG_FRAME_POINTER. However, there are only really three use cases for stack tracing: (a) Trace the current task, including IRQ stack if any (b) Trace the current task, but skip IRQ stack (c) Trace some other task In all cases, if CONFIG_FRAME_POINTER is not defined, bp should just be 0. If it _is_ defined, then - in case (a) bp should be gotten directly from the CPU's register, so the caller should pass NULL for regs, - in case (b) the caller should should pass the IRQ registers to dump_trace(), - in case (c) bp should be gotten from the top of the task's stack, so the caller should pass NULL for regs. Hence, the bp argument is not necessary because the combination of task and regs is sufficient to determine an appropriate value for bp. This patch introduces a new inline function stack_frame(task, regs) that computes the desired bp. This function is then called from the two versions of dump_stack(). Signed-off-by: Soren Sandmann <ssp@redhat.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@infradead.org>, Cc: Frederic Weisbecker <fweisbec@gmail.com>, Cc: Arnaldo Carvalho de Melo <acme@redhat.com>, LKML-Reference: <m3oc9rop28.fsf@dhcp-100-3-82.bos.redhat.com>> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86: Unify save_stack_address() and save_stack_address_nosched()Oleg Nesterov2010-06-091-14/+10
| | | | | | | | | | | | | Cleanup. Factor the common code in save_stack_address() and save_stack_address_nosched(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> LKML-Reference: <20100603193243.GA31534@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86: Make save_stack_address() !CONFIG_FRAME_POINTER friendlyOleg Nesterov2010-06-091-1/+5
| | | | | | | | | | | | | | | | | | | | | | If CONFIG_FRAME_POINTER=n, print_context_stack() shouldn't neglect the non-reliable addresses on stack, this is all we have if dump_trace(bp) is called with the wrong or zero bp. For example, /proc/pid/stack doesn't work if CONFIG_FRAME_POINTER=n. This patch obviously has no effect if CONFIG_FRAME_POINTER=y, otherwise it reverts 1650743c "x86: don't save unreliable stack trace entries". Also, remove the unnecessary type-cast. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Roland McGrath <roland@redhat.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Vegard Nossum <vegard.nossum@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <20100603193239.GA31530@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* x86: Unify dumpstack.h and stacktrace.hFrederic Weisbecker2010-06-081-3/+4
| | | | | | | | | | | | | | | | | | | | | | arch/x86/include/asm/stacktrace.h and arch/x86/kernel/dumpstack.h declare headers of objects that deal with the same topic. Actually most of the files that include stacktrace.h also include dumpstack.h Although dumpstack.h seems more reserved for internals of stack traces, those are quite often needed to define specialized stack trace operations. And perf event arch headers are going to need access to such low level operations anyway. So don't continue to bother with dumpstack.h as it's not anymore about isolated deep internals. v2: fix struct stack_frame definition conflict in sysprof Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Soeren Sandmann <sandmann@daimi.au.dk>
* perf events, x86/stacktrace: Make stack walking optionalFrederic Weisbecker2009-12-171-8/+10
| | | | | | | | | | | | | | | | | | | The current print_context_stack helper that does the stack walking job is good for usual stacktraces as it walks through all the stack and reports even addresses that look unreliable, which is nice when we don't have frame pointers for example. But we have users like perf that only require reliable stacktraces, and those may want a more adapted stack walker, so lets make this function a callback in stacktrace_ops that users can tune for their needs. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> LKML-Reference: <1261024834-5336-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: add save_stack_trace_bp() for tracing from a specific stack frameVegard Nossum2009-06-121-0/+7
| | | | | | | | | | | | | This will help kmemcheck (and possibly other debugging tools) since we can now simply pass regs->bp to the stack tracer instead of specifying the number of stack frames to skip, which is unreliable if gcc decides to inline functions, etc. Note that this makes the API incomplete for other architectures, but I expect that those can be updated lazily, e.g. when they need it. Cc: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
* x86/stacktrace: return 0 instead of -1 for stack opsSteven Rostedt2009-05-141-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we return -1 in the ops->stack for the stacktrace saving, we end up breaking out of the loop if the stack we are tracing is in the exception stack. This causes traces like: <idle>-0 [002] 34263.745825: raise_softirq_irqoff <-__blk_complete_request <idle>-0 [002] 34263.745826: <= 0 <= 0 <= 0 <= 0 <= 0 <= 0 <= 0 By returning "0" instead, the irq stack is saved as well, and we see: <idle>-0 [003] 883.280992: raise_softirq_irqoff <-__hrtimer_star t_range_ns <idle>-0 [003] 883.280992: <= hrtimer_start_range_ns <= tick_nohz_restart_sched_tick <= cpu_idle <= start_secondary <= <= 0 <= 0 [ Impact: record stacks from interrupts ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* x86: update copyrightsIngo Molnar2009-01-311-1/+1
| | | | Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing/stack-tracer: fix style issuesTörök Edwin2008-11-231-22/+29
| | | | | | | Impact: cleanup Signed-off-by: Török Edwin <edwintorok@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* tracing: add support for userspace stacktraces in tracing/iter_ctrlTörök Edwin2008-11-231-0/+57
| | | | | | | | | | | | | | | | | | | | | | Impact: add new (default-off) tracing visualization feature Usage example: mount -t debugfs nodev /sys/kernel/debug cd /sys/kernel/debug/tracing echo userstacktrace >iter_ctrl echo sched_switch >current_tracer echo 1 >tracing_enabled .... run application ... echo 0 >tracing_enabled Then read one of 'trace','latency_trace','trace_pipe'. To get the best output you can compile your userspace programs with frame pointers (at least glibc + the app you are tracing). Signed-off-by: Török Edwin <edwintorok@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* stacktrace: fix modular build, export print_stack_trace and save_stack_traceIngo Molnar2008-06-301-0/+2
| | | | | | | | | | | | | | | | | | fix: ERROR: "print_stack_trace" [kernel/backtracetest.ko] undefined! ERROR: "save_stack_trace" [kernel/backtracetest.ko] undefined! Signed-off-by: Ingo Molnar <mingo@elte.hu> and fix: Building modules, stage 2. MODPOST 376 modules ERROR: "print_stack_trace" [kernel/backtracetest.ko] undefined! make[1]: *** [__modpost] Error 1 Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: don't save unreliable stack trace entriesVegard Nossum2008-02-261-0/+4
| | | | | | | | | | | | | | | | Currently, there is no way for print_stack_trace() to determine whether a given stack trace entry was deemed reliable or not, simply because save_stack_trace() does not record this information. (Perhaps needless to say, this makes the saved stack traces A LOT harder to read, and probably with no other benefits, since debugging features that use save_stack_trace() most likely also require frame pointers, etc.) This patch reverts to the old behaviour of only recording the reliable trace entries for saved stack traces. Signed-off-by: Vegard Nossum <vegardno@ifi.uio.no> Acked-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: remove unneded castsJan Engelhardt2008-01-301-1/+1
| | | | | | | | x86: remove unneeded casts Signed-off-by: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: pull bp calculation earlier into the backtrace pathArjan van de Ven2008-01-301-3/+4
| | | | | | | | | | | | | | | Right now, we take the stack pointer early during the backtrace path, but only calculate bp several functions deep later, making it hard to reconcile the stack and bp backtraces (as well as showing several internal backtrace functions on the stack with bp based backtracing). This patch moves the bp taking to the same place we take the stack pointer; sadly this ripples through several layers of the back tracing stack, but it's not all that bad in the end I hope. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: add the capability to print fuzzy backtracesArjan van de Ven2008-01-301-1/+1
| | | | | | | | | | | | | | For enhancing the 32 bit EBP based backtracer, I need the capability for the backtracer to tell it's customer that an entry is either reliable or unreliable, and the backtrace printing code then needs to print the unreliable ones slightly different. This patch adds the basic capability, the next patch will add a user of this capability. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: nuke a ton of unused exportsThomas Gleixner2008-01-301-1/+0
| | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: latencytop supportArjan van de Ven2008-01-251-0/+27
| | | | | | | | LatencyTOP kernel infrastructure; it measures latencies in the scheduler and tracks it system wide and per process. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: constify stacktrace_opsJan Beulich2007-10-171-1/+1
| | | | | | | | | | | .. as they're never written to. [ tglx: arch/x86 adaptation ] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Delete filenames in comments.Dave Jones2007-10-131-2/+0
| | | | | | | | | | | | | | | Since the x86 merge, lots of files that referenced their own filenames are no longer correct. Rather than keep them up to date, just delete them, as they add no real value. Additionally: - fix up comment formatting in scx200_32.c - Remove a credit from myself in setup_64.c from a time when we had no SCM - remove longwinded history from tsc_32.c which can be figured out from git. Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* x86_64: move kernelThomas Gleixner2007-10-111-0/+54
Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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