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* x86: Don't use frame pointer to save old stack on irq entryFrederic Weisbecker2011-07-021-30/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | rbp is used in SAVE_ARGS_IRQ to save the old stack pointer in order to restore it later in ret_from_intr. It is convenient because we save its value in the irq regs and it's easily restored using the leave instruction. However this is a kind of abuse of the frame pointer which role is to help unwinding the kernel by chaining frames together, each node following the return address to the previous frame. But although we are breaking the frame by changing the stack pointer, there is no preceding return address before the new frame. Hence using the frame pointer to link the two stacks breaks the stack unwinders that find a random value instead of a return address here. There is no workaround that can work in every case. We are using the fixup_bp_irq_link() function to dereference that abused frame pointer in the case of non nesting interrupt (which means stack changed). But that doesn't fix the case of interrupts that don't change the stack (but we still have the unconditional frame link), which is the case of hardirq interrupting softirq. We have no way to detect this transition so the frame irq link is considered as a real frame pointer and the return address is dereferenced but it is still a spurious one. There are two possible results of this: either the spurious return address, a random stack value, luckily belongs to the kernel text and then the unwinding can continue and we just have a weird entry in the stack trace. Or it doesn't belong to the kernel text and unwinding stops there. This is the reason why stacktraces (including perf callchains) on irqs that interrupted softirqs don't work very well. To solve this, we don't save the old stack pointer on rbp anymore but we save it to a scratch register that we push on the new stack and that we pop back later on irq return. This preserves the whole frame chain without spurious return addresses in the middle and drops the need for the horrid fixup_bp_irq_link() workaround. And finally irqs that interrupt softirq are sanely unwinded. Before: 99.81% perf [kernel.kallsyms] [k] perf_pending_event | --- perf_pending_event irq_work_run smp_irq_work_interrupt irq_work_interrupt | |--41.60%-- __read | | | |--99.90%-- create_worker | | bench_sched_messaging | | cmd_bench | | run_builtin | | main | | __libc_start_main | --0.10%-- [...] After: 1.64% swapper [kernel.kallsyms] [k] perf_pending_event | --- perf_pending_event irq_work_run smp_irq_work_interrupt irq_work_interrupt | |--95.00%-- arch_irq_work_raise | irq_work_queue | __perf_event_overflow | perf_swevent_overflow | perf_swevent_event | perf_tp_event | perf_trace_softirq | __do_softirq | call_softirq | do_softirq | irq_exit | | | |--73.68%-- smp_apic_timer_interrupt | | apic_timer_interrupt | | | | | |--96.43%-- amd_e400_idle | | | cpu_idle | | | start_secondary Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jan Beulich <JBeulich@novell.com>
* x86: Fetch stack from regs when possible in dump_trace()Frederic Weisbecker2011-07-021-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When regs are passed to dump_stack(), we fetch the frame pointer from the regs but the stack pointer is taken from the current frame. Thus the frame and stack pointers may not come from the same context. For example this can result in the unwinder to think the context is in irq, due to the current value of the stack, but the frame pointer coming from the regs points to a frame from another place. It then tries to fix up the irq link but ends up dereferencing a random frame pointer that doesn't belong to the irq stack: [ 9131.706906] ------------[ cut here ]------------ [ 9131.707003] WARNING: at arch/x86/kernel/dumpstack_64.c:129 dump_trace+0x2aa/0x330() [ 9131.707003] Hardware name: AMD690VM-FMH [ 9131.707003] Perf: bad frame pointer = 0000000000000005 in callchain [ 9131.707003] Modules linked in: [ 9131.707003] Pid: 1050, comm: perf Not tainted 3.0.0-rc3+ #181 [ 9131.707003] Call Trace: [ 9131.707003] <IRQ> [<ffffffff8104bd4a>] warn_slowpath_common+0x7a/0xb0 [ 9131.707003] [<ffffffff8104be21>] warn_slowpath_fmt+0x41/0x50 [ 9131.707003] [<ffffffff8178b873>] ? bad_to_user+0x6d/0x10be [ 9131.707003] [<ffffffff8100c2da>] dump_trace+0x2aa/0x330 [ 9131.707003] [<ffffffff810107d3>] ? native_sched_clock+0x13/0x50 [ 9131.707003] [<ffffffff8101b164>] perf_callchain_kernel+0x54/0x70 [ 9131.707003] [<ffffffff810d391f>] perf_prepare_sample+0x19f/0x2a0 [ 9131.707003] [<ffffffff810d546c>] __perf_event_overflow+0x16c/0x290 [ 9131.707003] [<ffffffff810d5430>] ? __perf_event_overflow+0x130/0x290 [ 9131.707003] [<ffffffff810107d3>] ? native_sched_clock+0x13/0x50 [ 9131.707003] [<ffffffff8100fbb9>] ? sched_clock+0x9/0x10 [ 9131.707003] [<ffffffff810752e5>] ? T.375+0x15/0x90 [ 9131.707003] [<ffffffff81084da4>] ? trace_hardirqs_on_caller+0x64/0x180 [ 9131.707003] [<ffffffff810817bd>] ? trace_hardirqs_off+0xd/0x10 [ 9131.707003] [<ffffffff810d5764>] perf_event_overflow+0x14/0x20 [ 9131.707003] [<ffffffff810d588c>] perf_swevent_hrtimer+0x11c/0x130 [ 9131.707003] [<ffffffff817821a1>] ? error_exit+0x51/0xb0 [ 9131.707003] [<ffffffff81072e93>] __run_hrtimer+0x83/0x1e0 [ 9131.707003] [<ffffffff810d5770>] ? perf_event_overflow+0x20/0x20 [ 9131.707003] [<ffffffff81073256>] hrtimer_interrupt+0x106/0x250 [ 9131.707003] [<ffffffff812a3bfd>] ? trace_hardirqs_off_thunk+0x3a/0x3c [ 9131.707003] [<ffffffff81024833>] smp_apic_timer_interrupt+0x53/0x90 [ 9131.707003] [<ffffffff81789053>] apic_timer_interrupt+0x13/0x20 [ 9131.707003] <EOI> [<ffffffff817821a1>] ? error_exit+0x51/0xb0 [ 9131.707003] [<ffffffff8178219c>] ? error_exit+0x4c/0xb0 [ 9131.707003] ---[ end trace b2560d4876709347 ]--- Fix this by simply taking the stack pointer from regs->sp when regs are provided. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
* x86, dumpstack: Correct stack dump info when frame pointer is availableNamhyung Kim2011-03-181-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* x86-64: Don't use pointer to out-of-scope variable in dump_trace()Jesper Juhl2011-01-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In arch/x86/kernel/dumpstack_64.c::dump_trace() we have this code: ... if (!stack) { unsigned long dummy; stack = &dummy; if (task && task != current) stack = (unsigned long *)task->thread.sp; } bp = stack_frame(task, regs); /* * Print function call entries in all stacks, starting at the * current stack address. If the stacks consist of nested * exceptions */ tinfo = task_thread_info(task); for (;;) { char *id; unsigned long *estack_end; estack_end = in_exception_stack(cpu, (unsigned long)stack, &used, &id); ... You'll notice that we assign to 'stack' the address of the variable 'dummy' which is only in-scope inside the 'if (!stack)'. So when we later access stack (at the end of the above, and assuming we did not take the 'if (task && task != current)' branch) we'll be using the address of a variable that is no longer in scope. I believe this patch is the proper fix, but I freely admit that I'm not 100% certain. Signed-off-by: Jesper Juhl <jj@chaosbits.net> LKML-Reference: <alpine.LNX.2.00.1101242232590.10252@swampdragon.chaosbits.net> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* x86: Eliminate bp argument from the stack tracing routinesSoeren Sandmann Pedersen2010-11-181-17/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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, printk: Get rid of <0> from stack outputJiri Slaby2010-10-231-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The stack output currently looks like this: 7fffffffffffffff 0000000a00000000 ffffffff81093341 0000000000000046 <0> ffff88003a545fd8 0000000000000000 0000000000000000 00007fffa39769c0 <0> ffff88003e403f58 ffffffff8102fc4c ffff88003e403f58 ffff88003e403f78 The superfluous <0> are caused by recent printk KERN_CONT change. <*> is now ignored in printk unless some text follows the level and even then it still has to be the first in the format message. Note that the log_lvl parameter is now completely ignored in show_stack_log_lvl and the stack is dumped with the default level (like for quite some time already). It behaves the same as the rest of the dump, function traces are dumped in the very same manner. Only Code and maybe some lines are printed with EMERG level. Unfortunately I see no way how to fix this conceptually to have the whole oops/BUG/panic output with the same level, so this removed only the superfluous characters for the time being. Just for illustration: <4>Process kworker/0:0 (pid: 0, threadinfo ffff88003c8a6000, task ffff88003c85c100) <0>Stack: <4> ffffffff818022c0 0000000a00000001 0000000000000001 0000000000000046 <4> ffff88003c8a7fd8 0000000000000001 ffff88003c8a7e58 0000000000000000 <4> ffff88003e503f48 ffffffff8102fc4c ffff88003e503f48 ffff88003e503f68 <0>Call Trace: <0> <IRQ> <4> [<ffffffff8102fc4c>] ? call_softirq+0x1c/0x30 ... <0>Code: 00 01 00 00 65 8b 04 25 80 c5 00 00 c7 45 ... Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: jirislaby@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <1287586131-16222-1-git-send-email-jslaby@suse.cz> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: Unify dumpstack.h and stacktrace.hFrederic Weisbecker2010-06-081-1/+0
| | | | | | | | | | | | | | | | | | | | | | 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/x86-64: Use frame pointer to walk on irq and process stacksFrederic Weisbecker2010-03-101-2/+2
| | | | | | | | | | | | | | | We were using the frame pointer based stack walker on every contexts in x86-32, but not in x86-64 where we only use the seven-league boots on the exception stacks. Use it also on irq and process stacks. This utterly accelerate the captures. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
* Merge commit 'v2.6.34-rc1' into perf/urgentIngo Molnar2010-03-091-0/+1
|\ | | | | | | | | | | | | | | | | Conflicts: tools/perf/util/probe-event.c Merge reason: Pick up -rc1 and resolve the conflict as well. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2010-02-281-5/+0
| |\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (172 commits) perf_event, amd: Fix spinlock initialization perf_event: Fix preempt warning in perf_clock() perf tools: Flush maps on COMM events perf_events, x86: Split PMU definitions into separate files perf annotate: Handle samples not at objdump output addr boundaries perf_events, x86: Remove superflous MSR writes perf_events: Simplify code by removing cpu argument to hw_perf_group_sched_in() perf_events, x86: AMD event scheduling perf_events: Add new start/stop PMU callbacks perf_events: Report the MMAP pgoff value in bytes perf annotate: Defer allocating sym_priv->hist array perf symbols: Improve debugging information about symtab origins perf top: Use a macro instead of a constant variable perf symbols: Check the right return variable perf/scripts: Tag syscall_name helper as not yet available perf/scripts: Add perf-trace-python Documentation perf/scripts: Remove unnecessary PyTuple resizes perf/scripts: Add syscall tracing scripts perf/scripts: Add Python scripting engine perf/scripts: Remove check-perf-trace from listed scripts ... Fix trivial conflict in tools/perf/util/probe-event.c
| * | x86_64: Print modules like i386 doesAlexey Dobriyan2010-02-041-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Print modules list during kernel BUG. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'perf/urgent' of ↵Ingo Molnar2010-03-041-2/+8
|\ \ \ | |_|/ |/| | | | | git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into perf/urgent
| * | x86/stacktrace: Don't dereference bad frame pointersFrederic Weisbecker2010-03-031-2/+8
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Callers of a stacktrace might pass bad frame pointers. Those are usually checked for safety in stack walking helpers before any dereferencing, but this is not the case when we need to go through one more frame pointer that backlinks the irq stack to the previous one, as we don't have any reliable address boudaries to compare this frame pointer against. This raises crashes when we record callchains for ftrace events with perf because we don't use the right helpers to capture registers there. We get wrong frame pointers as we call task_pt_regs() even on kernel threads, which is a wrong thing as it gives us the initial state of any kernel threads freshly created. This is even not what we want for user tasks. What we want is a hot snapshot of registers when the ftrace event triggers, not the state before a task entered the kernel. This requires more thoughts to do it correctly though. So first put a guardian to ensure the given frame pointer can be dereferenced to avoid crashes. We'll think about how to fix the callers in a subsequent patch. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: 2.6.33.x <stable@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
* | perf: Drop useless check for ignored frameFrederic Weisbecker2010-01-131-5/+0
|/ | | | | | | | | | | | | The check that ignores the debug and nmi stack frames is useless now that we have a frame pointer that makes us start at the right place. We don't anymore have to deal with these. 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: <1262235183-5320-2-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* perf events, x86/stacktrace: Make stack walking optionalFrederic Weisbecker2009-12-171-2/+2
| | | | | | | | | | | | | | | | | | | 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>
* Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds2009-12-111-1/+32
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (57 commits) x86, perf events: Check if we have APIC enabled perf_event: Fix variable initialization in other codepaths perf kmem: Fix unused argument build warning perf symbols: perf_header__read_build_ids() offset'n'size should be u64 perf symbols: dsos__read_build_ids() should read both user and kernel buildids perf tools: Align long options which have no short forms perf kmem: Show usage if no option is specified sched: Mark sched_clock() as notrace perf sched: Add max delay time snapshot perf tools: Correct size given to memset perf_event: Fix perf_swevent_hrtimer() variable initialization perf sched: Fix for getting task's execution time tracing/kprobes: Fix field creation's bad error handling perf_event: Cleanup for cpu_clock_perf_event_update() perf_event: Allocate children's perf_event_ctxp at the right time perf_event: Clean up __perf_event_init_context() hw-breakpoints: Modify breakpoints without unregistering them perf probe: Update perf-probe document perf probe: Support --del option trace-kprobe: Support delete probe syntax ...
| * x86: Fixup wrong irq frame link in stacktracesFrederic Weisbecker2009-12-061-1/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When we enter in irq, two things can happen to preserve the link to the previous frame pointer: - If we were in an irq already, we don't switch to the irq stack as we are inside. We just need to save the previous frame pointer and to link the new one to the previous. - Otherwise we need another level of indirection. We enter the irq with the previous stack. We save the previous bp inside and make bp pointing to its saved address. Then we switch to the irq stack and push bp another time but to the new stack. This makes two levels to dereference instead of one. In the second case, the current stacktrace code omits the second level and loses the frame pointer accuracy. The stack that follows will then be considered as unreliable. Handling that makes the perf callchain happier. Before: 43.94% [k] _raw_read_lock | --- _read_lock | |--60.53%-- send_sigio | __kill_fasync | kill_fasync | evdev_pass_event | evdev_event | input_pass_event | input_handle_event | input_event | synaptics_process_byte | psmouse_handle_byte | psmouse_interrupt | serio_interrupt | i8042_interrupt | handle_IRQ_event | handle_edge_irq | handle_irq | __irqentry_text_start | ret_from_intr | | | |--30.43%-- __select | | | |--17.39%-- 0x454f15 | | | |--13.04%-- __read | | | |--13.04%-- vread_hpet | | | |--13.04%-- _xcb_lock_io | | | --13.04%-- 0x7f630878ce8 After: 50.00% [k] _raw_read_lock | --- _read_lock | |--98.97%-- send_sigio | __kill_fasync | kill_fasync | evdev_pass_event | evdev_event | input_pass_event | input_handle_event | input_event | | | |--96.88%-- synaptics_process_byte | | psmouse_handle_byte | | psmouse_interrupt | | serio_interrupt | | i8042_interrupt | | handle_IRQ_event | | handle_edge_irq | | handle_irq | | __irqentry_text_start | | ret_from_intr | | | | | |--39.78%-- __const_udelay | | | | | | | |--91.89%-- ath5k_hw_register_timeout | | | | ath5k_hw_noise_floor_calibration | | | | ath5k_hw_reset | | | | ath5k_reset | | | | ath5k_config | | | | ieee80211_hw_config | | | | | | | | | |--88.24%-- ieee80211_scan_work | | | | | worker_thread | | | | | kthread | | | | | child_rip | | | | | | | | | --11.76%-- ieee80211_scan_completed | | | | ieee80211_scan_work | | | | worker_thread | | | | kthread | | | | child_rip | | | | | | | --8.11%-- ath5k_hw_noise_floor_calibration | | | ath5k_hw_reset | | | ath5k_reset | | | ath5k_config Note: This does not only affect perf events but also x86-64 stacktraces. They were considered as unreliable once we quit the irq stack frame. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: "K. Prasad" <prasad@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com>
* | x86: dumpstack, 64-bit: Disable preemption when walking the IRQ/exception stacksIngo Molnar2009-11-261-8/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This warning: [ 847.140022] rb_producer D 0000000000000000 5928 519 2 0x00000000 [ 847.203627] BUG: using smp_processor_id() in preemptible [00000000] code: khungtaskd/517 [ 847.207360] caller is show_stack_log_lvl+0x2e/0x241 [ 847.210364] Pid: 517, comm: khungtaskd Not tainted 2.6.32-rc8-tip+ #13761 [ 847.213395] Call Trace: [ 847.215847] [<ffffffff81413bde>] debug_smp_processor_id+0x1f0/0x20a [ 847.216809] [<ffffffff81015eae>] show_stack_log_lvl+0x2e/0x241 [ 847.220027] [<ffffffff81018512>] show_stack+0x1c/0x1e [ 847.223365] [<ffffffff8107b7db>] sched_show_task+0xe4/0xe9 [ 847.226694] [<ffffffff8112f21f>] check_hung_task+0x140/0x199 [ 847.230261] [<ffffffff8112f4a8>] check_hung_uninterruptible_tasks+0x1b7/0x20f [ 847.233371] [<ffffffff8112f500>] ? watchdog+0x0/0x50 [ 847.236683] [<ffffffff8112f54e>] watchdog+0x4e/0x50 [ 847.240034] [<ffffffff810cee56>] kthread+0x97/0x9f [ 847.243372] [<ffffffff81012aea>] child_rip+0xa/0x20 [ 847.246690] [<ffffffff81e43494>] ? restore_args+0x0/0x30 [ 847.250019] [<ffffffff81e43083>] ? _spin_lock+0xe/0x10 [ 847.253351] [<ffffffff810cedbf>] ? kthread+0x0/0x9f [ 847.256833] [<ffffffff81012ae0>] ? child_rip+0x0/0x20 Happens because on preempt-RCU, khungd calls show_stack() with preemption enabled. Make sure we are not preemptible while walking the IRQ and exception stacks on 64-bit. (32-bit stack dumping is preemption safe.) Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | x86: dumpstack: Clean up the x86_stack_ids[][] initalization and other detailsIngo Molnar2009-11-261-12/+13
|/ | | | | | | | | | Make the initialization more readable, plus tidy up a few small visual details as well. No change in functionality. LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* headers: utsname.h reduxAlexey Dobriyan2009-09-231-1/+0
| | | | | | | | | | | | | * remove asm/atomic.h inclusion from linux/utsname.h -- not needed after kref conversion * remove linux/utsname.h inclusion from files which do not need it NOTE: it looks like fs/binfmt_elf.c do not need utsname.h, however due to some personality stuff it _is_ needed -- cowardly leave ELF-related headers and files alone. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* perf_counter: Ignore the nmi call frames in the x86-64 backtracesFrederic Weisbecker2009-07-011-7/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | About every callchains recorded with perf record are filled up including the internal perfcounter nmi frame: perf_callchain perf_counter_overflow intel_pmu_handle_irq perf_counter_nmi_handler notifier_call_chain atomic_notifier_call_chain notify_die do_nmi nmi We want ignore this frame as it's not interesting for instrumentation. To solve this, we simply ignore every frames from nmi context. New example of "perf report -s sym -c" after this patch: 9.59% [k] search_by_key 4.88% search_by_key reiserfs_read_locked_inode reiserfs_iget reiserfs_lookup do_lookup __link_path_walk path_walk do_path_lookup user_path_at vfs_fstatat vfs_lstat sys_newlstat system_call_fastpath __lxstat 0x406fb1 3.19% search_by_key search_by_entry_key reiserfs_find_entry reiserfs_lookup do_lookup __link_path_walk path_walk do_path_lookup user_path_at vfs_fstatat vfs_lstat sys_newlstat system_call_fastpath __lxstat 0x406fb1 [...] For now this patch only solves the problem in x86-64. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Anton Blanchard <anton@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <1246474930-6088-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit.Brian Gerst2009-01-191-1/+1
| | | | | Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* x86-64: Convert irqstacks to per-cpuBrian Gerst2009-01-191-16/+17
| | | | | | | | | | | | | | | | | | | | Move the irqstackptr variable from the PDA to per-cpu. Make the stacks themselves per-cpu, removing some specific allocation code. Add a seperate flag (is_boot_cpu) to simplify the per-cpu boot adjustments. tj: * sprinkle some underbars around. * irq_stack_ptr is not used till traps_init(), no reason to initialize it early. On SMP, just leaving it NULL till proper initialization in setup_per_cpu_areas() works. Dropped is_boot_cpu and early irq_stack_ptr initialization. * do DECLARE/DEFINE_PER_CPU(char[IRQ_STACK_SIZE], irq_stack) instead of (char, irq_stack[IRQ_STACK_SIZE]). Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* ftrace: print real return in dumpstack for function graphSteven Rostedt2008-12-031-3/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: better dumpstack output I noticed in my crash dumps and even in the stack tracer that a lot of functions listed in the stack trace are simply return_to_handler which is ftrace graphs way to insert its own call into the return of a function. But we lose out where the actually function was called from. This patch adds in hooks to the dumpstack mechanism that detects this and finds the real function to print. Both are printed to let the user know that a hook is still in place. This does give a funny side effect in the stack tracer output: Depth Size Location (80 entries) ----- ---- -------- 0) 4144 48 save_stack_trace+0x2f/0x4d 1) 4096 128 ftrace_call+0x5/0x2b 2) 3968 16 mempool_alloc_slab+0x16/0x18 3) 3952 384 return_to_handler+0x0/0x73 4) 3568 -240 stack_trace_call+0x11d/0x209 5) 3808 144 return_to_handler+0x0/0x73 6) 3664 -128 mempool_alloc+0x4d/0xfe 7) 3792 128 return_to_handler+0x0/0x73 8) 3664 -32 scsi_sg_alloc+0x48/0x4a [scsi_mod] As you can see, the real functions are now negative. This is due to them not being found inside the stack. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86: unify appropriate bits from dumpstack_32 and dumpstack_64Neil Horman2008-10-271-283/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup As promised, now that dumpstack_32 and dumpstack_64 have so many bits in common, we should merge the in-sync bits into a common file, to prevent them from diverging again. This patch removes bits which are common between dumpstack_32.c and dumpstack_64.c and places them in a common dumpstack.c which is built for both 32 and 64 bit arches. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu> Makefile | 2 arch/x86/kernel/Makefile | 2 arch/x86/kernel/Makefile | 2 arch/x86/kernel/Makefile | 2 arch/x86/kernel/Makefile | 2 arch/x86/kernel/Makefile | 2 arch/x86/kernel/dumpstack.c | 319 +++++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/dumpstack.h | 39 +++++ arch/x86/kernel/dumpstack_32.c | 294 ------------------------------------- arch/x86/kernel/dumpstack_64.c | 285 ------------------------------------ 5 files changed, 363 insertions(+), 576 deletions(-)
* i386, dumpstack: unify die()Alexander van Heukelum2008-10-221-1/+5
| | | | | | | | | | | Make i386's die() equal to x86_64's version. Whitespace-only changes on x86_64, to make it equal to i386's version. (user_mode and user_mode_vm are equal on x86_64.) Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* i386, dumpstack: use oops_begin/oops_end in die_nmiAlexander van Heukelum2008-10-221-2/+2
| | | | | | | | | | | Use oops_begin and oops_end in die_nmi. Whitespace-only changes on x86_64, to make it equal to i386's version. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, dumpstack: always call oops_exit from oops_endAlexander van Heukelum2008-10-221-6/+5
| | | | | | | | | | | | Always call oops_exit from oops_end, even if signr==0. Also, move add_taint(TAINT_DIE) from __die to oops_end on x86_64 and interchange two lines to make oops_end more similar to the i386-version. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86_64, dumpstack: move kexec_crash from __die to oops_endAlexander van Heukelum2008-10-221-5/+4
| | | | | | | | | | | oops_end is preceded by either a call to __die, or a conditional call to crash_kexec. Move the conditional call to crash_kexec from the end of __die to the start of oops_end and remove the superfluous call to crash_kexec in die_nmi. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86, dumpstack: let signr=0 signal no do_exitAlexander van Heukelum2008-10-221-4/+5
| | | | | | | | | | | | | | | Change oops_end such that signr=0 signals that do_exit is not to be called. Currently, each use of __die is soon followed by a call to oops_end and 'regs' is set to NULL if oops_end is expected not to call do_exit. Change all such pairs to set signr=0 instead. On x86_64 oops_end is used 'bare' in die_nmi; use signr=0 instead of regs=NULL there, too. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sysfs: crash debuggingAndrew Morton2008-10-161-0/+2
| | | | | | | | | | | | Print the name of the last-accessed sysfs file when we oops, to help track down oopses which occur in sysfs store/read handlers. Because these oopses tend to not leave any trace of the offending code in the stack traces. Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* dumpstack: x86: various small unification steps, fixAlexander van Heukelum2008-10-131-1/+1
| | | | | | | | | | | | | | | After "dumpstack: x86: various small unification steps", the assembler gives the following compile error. The error is in dumpstack_64.c. {standard input}: Assembler messages: {standard input}:720: Error: Incorrect register `%rbx' used with `l' suffix {standard input}:1340: Error: Incorrect register `%r12' used with `l' suffix Indeed the suffix in get_bp() was wrong. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* dumpstack: x86: various small unification stepsAlexander van Heukelum2008-10-131-6/+9
| | | | | | | | | | | | - define STACKSLOTS_PER_LINE and use it - define get_bp macro to hide the %%ebp/%%rbp difference - i386: check task==NULL in dump_trace, like x86_64 - i386: show_trace(NULL, ...) uses current automatically - x86_64: use [#%d] for die_counter, like i386 - whitespace and comments Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* dumpstack: x86: use log_lvl and unify trace formattingAlexander van Heukelum2008-10-131-4/+4
| | | | | | | | | - x86: Write log_lvl strings if available - start raw stack dumps on new line - i386: Remove extra indentation for raw stack dumps Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* dumptrace: x86: consistently include loglevel, print stack switchAlexander van Heukelum2008-10-131-2/+7
| | | | | | | | | | | | - i386 and x86_64: always printk the 'data' parameter - i386: announce stack switch (irq -> normal) - i386: check if there is a stack switch before announcing it There is a warning that 'context' might come out corrupt in early boot. If this is true it should be fixed, not worked around. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* dumpstack: x86: add "end" parameter to valid_stack_ptr and print_context_stackAlexander van Heukelum2008-10-131-1/+1
| | | | | | | | - Add "end" parameter to valid_stack_ptr and print_context_stack - use sizeof(long) as the size of a word on the stack Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* dumpstack: x86: make printk_address equalAlexander van Heukelum2008-10-131-2/+2
| | | | | | | | | | | | - x86_64: use %p to print an address - make i386-version the same as the above The result should be the same on x86_64; on i386 the output only changes if CONFIG_KALLSYMS is turned off, in which case the address is printed twice. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* x86_64: split out dumpstack code from traps_64.cAlexander van Heukelum2008-10-131-0/+565
The dumpstack code is logically quite independent from the hardware traps. Split it out into its own file. Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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