From: Greg Kroah-Hartman Date: Sun, 17 Apr 2016 12:15:25 +0000 (-0700) Subject: 3.14-stable patches X-Git-Tag: v3.14.67~8 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e390586b5f045ff81dc46bbb35aab36f634cdd77;p=thirdparty%2Fkernel%2Fstable-queue.git 3.14-stable patches added patches: perf-cure-event-pending_disable-race.patch --- diff --git a/queue-3.14/perf-cure-event-pending_disable-race.patch b/queue-3.14/perf-cure-event-pending_disable-race.patch new file mode 100644 index 00000000000..7b85f754a11 --- /dev/null +++ b/queue-3.14/perf-cure-event-pending_disable-race.patch @@ -0,0 +1,67 @@ +From 28a967c3a2f99fa3b5f762f25cb2a319d933571b Mon Sep 17 00:00:00 2001 +From: Peter Zijlstra +Date: Wed, 24 Feb 2016 18:45:46 +0100 +Subject: perf: Cure event->pending_disable race + +From: Peter Zijlstra + +commit 28a967c3a2f99fa3b5f762f25cb2a319d933571b upstream. + +Because event_sched_out() checks event->pending_disable _before_ +actually disabling the event, it can happen that the event fires after +it checks but before it gets disabled. + +This would leave event->pending_disable set and the queued irq_work +will try and process it. + +However, if the event trigger was during schedule(), the event might +have been de-scheduled by the time the irq_work runs, and +perf_event_disable_local() will fail. + +Fix this by checking event->pending_disable _after_ we call +event->pmu->del(). This depends on the latter being a compiler +barrier, such that the compiler does not lift the load and re-creates +the problem. + +Tested-by: Alexander Shishkin +Signed-off-by: Peter Zijlstra (Intel) +Reviewed-by: Alexander Shishkin +Cc: Arnaldo Carvalho de Melo +Cc: Jiri Olsa +Cc: Linus Torvalds +Cc: Peter Zijlstra +Cc: Thomas Gleixner +Cc: dvyukov@google.com +Cc: eranian@google.com +Cc: oleg@redhat.com +Cc: panand@redhat.com +Cc: sasha.levin@oracle.com +Cc: vince@deater.net +Link: http://lkml.kernel.org/r/20160224174948.040469884@infradead.org +Signed-off-by: Ingo Molnar +Signed-off-by: Greg Kroah-Hartman + +--- + kernel/events/core.c | 6 +++--- + 1 file changed, 3 insertions(+), 3 deletions(-) + +--- a/kernel/events/core.c ++++ b/kernel/events/core.c +@@ -1400,14 +1400,14 @@ event_sched_out(struct perf_event *event + + perf_pmu_disable(event->pmu); + ++ event->tstamp_stopped = tstamp; ++ event->pmu->del(event, 0); ++ event->oncpu = -1; + event->state = PERF_EVENT_STATE_INACTIVE; + if (event->pending_disable) { + event->pending_disable = 0; + event->state = PERF_EVENT_STATE_OFF; + } +- event->tstamp_stopped = tstamp; +- event->pmu->del(event, 0); +- event->oncpu = -1; + + if (!is_software_event(event)) + cpuctx->active_oncpu--; diff --git a/queue-3.14/series b/queue-3.14/series index b4538b4ed5e..1d84fedca3b 100644 --- a/queue-3.14/series +++ b/queue-3.14/series @@ -27,3 +27,4 @@ mac80211-fix-unnecessary-frame-drops-in-mesh-fwding.patch usb-renesas_usbhs-avoid-null-pointer-derefernce-in-usbhsf_pkt_handler.patch usb-renesas_usbhs-disable-tx-irq-before-starting-tx-dmac-transfer.patch ext4-add-lockdep-annotations-for-i_data_sem.patch +perf-cure-event-pending_disable-race.patch