user/sven/linux.git/kernel/events, branch v3.10.93

perf: Fix fasync handling on inherited events

2015-09-13T16:07:59Z

commit fed66e2cdd4f127a43fd11b8d92a99bdd429528c upstream. Vince reported that the fasync signal stuff doesn't work proper for inherited events. So fix that. Installing fasync allocates memory and sets filp->f_flags |= FASYNC, which upon the demise of the file descriptor ensures the allocation is freed and state is updated. Now for perf, we can have the events stick around for a while after the original FD is dead because of references from child events. So we cannot copy the fasync pointer around. We can however consistently use the parent's fasync, as that will be updated. Reported-and-Tested-by: Vince Weaver Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho deMelo Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: eranian@google.com Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twins Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Fix irq_work 'tail' recursion

2015-04-13T12:02:12Z

commit d525211f9d1be8b523ec7633f080f2116f5ea536 upstream. Vince reported a watchdog lockup like: [] perf_tp_event+0xc4/0x210 [] perf_trace_lock+0x12a/0x160 [] lock_release+0x130/0x260 [] _raw_spin_unlock_irqrestore+0x24/0x40 [] do_send_sig_info+0x5d/0x80 [] send_sigio_to_task+0x12f/0x1a0 [] send_sigio+0xae/0x100 [] kill_fasync+0x97/0xf0 [] perf_event_wakeup+0xd4/0xf0 [] perf_pending_event+0x33/0x60 [] irq_work_run_list+0x4c/0x80 [] irq_work_run+0x18/0x40 [] smp_trace_irq_work_interrupt+0x3f/0xc0 [] trace_irq_work_interrupt+0x6d/0x80 Which is caused by an irq_work generating new irq_work and therefore not allowing forward progress. This happens because processing the perf irq_work triggers another perf event (tracepoint stuff) which in turn generates an irq_work ad infinitum. Avoid this by raising the recursion counter in the irq_work -- which effectively disables all software events (including tracepoints) from actually triggering again. Reported-by: Vince Weaver Tested-by: Vince Weaver Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Paul Mackerras Cc: Steven Rostedt Link: http://lkml.kernel.org/r/20150219170311.GH21418@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Fix events installation during moving group

2015-01-16T14:59:03Z

commit 9fc81d87420d0d3fd62d5e5529972c0ad9eab9cc upstream. We allow PMU driver to change the cpu on which the event should be installed to. This happened in patch: e2d37cd213dc ("perf: Allow the PMU driver to choose the CPU on which to install events") This patch also forces all the group members to follow the currently opened events cpu if the group happened to be moved. This and the change of event->cpu in perf_install_in_context() function introduced in: 0cda4c023132 ("perf: Introduce perf_pmu_migrate_context()") forces group members to change their event->cpu, if the currently-opened-event's PMU changed the cpu and there is a group move. Above behaviour causes problem for breakpoint events, which uses event->cpu to touch cpu specific data for breakpoints accounting. By changing event->cpu, some breakpoints slots were wrongly accounted for given cpu. Vinces's perf fuzzer hit this issue and caused following WARN on my setup: WARNING: CPU: 0 PID: 20214 at arch/x86/kernel/hw_breakpoint.c:119 arch_install_hw_breakpoint+0x142/0x150() Can't find any breakpoint slot [...] This patch changes the group moving code to keep the event's original cpu. Reported-by: Vince Weaver Signed-off-by: Jiri Olsa Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Vince Weaver Cc: Yan, Zheng Link: http://lkml.kernel.org/r/1418243031-20367-3-git-send-email-jolsa@kernel.org Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

uprobes, x86: Fix _TIF_UPROBE vs _TIF_NOTIFY_RESUME

2014-12-06T23:05:46Z

commit 82975bc6a6df743b9a01810fb32cb65d0ec5d60b upstream. x86 call do_notify_resume on paranoid returns if TIF_UPROBE is set but not on non-paranoid returns. I suspect that this is a mistake and that the code only works because int3 is paranoid. Setting _TIF_NOTIFY_RESUME in the uprobe code was probably a workaround for the x86 bug. With that bug fixed, we can remove _TIF_NOTIFY_RESUME from the uprobes code. Reported-by: Oleg Nesterov Acked-by: Srikar Dronamraju Acked-by: Borislav Petkov Signed-off-by: Andy Lutomirski Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

perf: Handle compat ioctl

2014-11-21T17:22:55Z

commit b3f207855f57b9c8f43a547a801340bb5cbc59e5 upstream. When running a 32-bit userspace on a 64-bit kernel (eg. i386 application on x86_64 kernel or 32-bit arm userspace on arm64 kernel) some of the perf ioctls must be treated with special care, as they have a pointer size encoded in the command. For example, PERF_EVENT_IOC_ID in 32-bit world will be encoded as 0x80042407, but 64-bit kernel will expect 0x80082407. In result the ioctl will fail returning -ENOTTY. This patch solves the problem by adding code fixing up the size as compat_ioctl file operation. Reported-by: Drew Richardson Signed-off-by: Pawel Moll Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1402671812-9078-1-git-send-email-pawel.moll@arm.com Signed-off-by: Ingo Molnar Signed-off-by: David Ahern Signed-off-by: Greg Kroah-Hartman

perf: fix perf bug in fork()

2014-10-09T19:18:42Z

commit 6c72e3501d0d62fc064d3680e5234f3463ec5a86 upstream. Oleg noticed that a cleanup by Sylvain actually uncovered a bug; by calling perf_event_free_task() when failing sched_fork() we will not yet have done the memset() on ->perf_event_ctxp[] and will therefore try and 'free' the inherited contexts, which are still in use by the parent process. This is bad.. Suggested-by: Oleg Nesterov Reported-by: Oleg Nesterov Reported-by: Sylvain 'ythier' Hitier Signed-off-by: Peter Zijlstra (Intel) Cc: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

perf: Fix a race condition in perf_remove_from_context()

2014-10-05T21:54:14Z

commit 3577af70a2ce4853d58e57d832e687d739281479 upstream. We saw a kernel soft lockup in perf_remove_from_context(), it looks like the `perf` process, when exiting, could not go out of the retry loop. Meanwhile, the target process was forking a child. So either the target process should execute the smp function call to deactive the event (if it was running) or it should do a context switch which deactives the event. It seems we optimize out a context switch in perf_event_context_sched_out(), and what's more important, we still test an obsolete task pointer when retrying, so no one actually would deactive that event in this situation. Fix it directly by reloading the task pointer in perf_remove_from_context(). This should cure the above soft lockup. Signed-off-by: Cong Wang Signed-off-by: Cong Wang Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Linus Torvalds Link: http://lkml.kernel.org/r/1409696840-843-1-git-send-email-xiyou.wangcong@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

perf: Enforce 1 as lower limit for perf_event_max_sample_rate

2014-06-11T19:03:27Z

commit 723478c8a471403c53cf144999701f6e0c4bbd11 upstream. /proc/sys/kernel/perf_event_max_sample_rate will accept negative values as well as 0. Negative values are unreasonable, and 0 causes a divide by zero exception in perf_proc_update_handler. This patch enforces a lower limit of 1. Signed-off-by: Knut Petersen Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/5242DB0C.4070005@t-online.de Signed-off-by: Ingo Molnar Cc: Weng Meiling Signed-off-by: Greg Kroah-Hartman

perf: Fix interrupt handler timing harness

2014-06-11T19:03:27Z

commit e5302920da9ef23f9d19d4e9ac85704cc25bee7a upstream. This patch fixes a serious bug in: 14c63f17b1fd perf: Drop sample rate when sampling is too slow There was an misunderstanding on the API of the do_div() macro. It returns the remainder of the division and this was not what the function expected leading to disabling the interrupt latency watchdog. This patch also remove a duplicate assignment in perf_sample_event_took(). Signed-off-by: Stephane Eranian Cc: peterz@infradead.org Cc: dave.hansen@linux.intel.com Cc: ak@linux.intel.com Cc: jolsa@redhat.com Link: http://lkml.kernel.org/r/20130704223010.GA30625@quad Signed-off-by: Ingo Molnar Cc: Weng Meiling Signed-off-by: Greg Kroah-Hartman

perf: Drop sample rate when sampling is too slow

2014-06-11T19:03:26Z

commit 14c63f17b1fde5a575a28e96547a22b451c71fb5 upstream. This patch keeps track of how long perf's NMI handler is taking, and also calculates how many samples perf can take a second. If the sample length times the expected max number of samples exceeds a configurable threshold, it drops the sample rate. This way, we don't have a runaway sampling process eating up the CPU. This patch can tend to drop the sample rate down to level where perf doesn't work very well. *BUT* the alternative is that my system hangs because it spends all of its time handling NMIs. I'll take a busted performance tool over an entire system that's busted and undebuggable any day. BTW, my suspicion is that there's still an underlying bug here. Using the HPET instead of the TSC is definitely a contributing factor, but I suspect there are some other things going on. But, I can't go dig down on a bug like that with my machine hanging all the time. Signed-off-by: Dave Hansen Acked-by: Peter Zijlstra Cc: paulus@samba.org Cc: acme@ghostprotocols.net Cc: Dave Hansen [ Prettified it a bit. ] Signed-off-by: Ingo Molnar Cc: Weng Meiling Signed-off-by: Greg Kroah-Hartman