From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:35895 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759149AbcDIScs (ORCPT ); Sat, 9 Apr 2016 14:32:48 -0400 Subject: Patch "perf/core: Fix perf_sched_count derailment" has been added to the 4.5-stable tree To: alexander.shishkin@linux.intel.com, acme@infradead.org, acme@redhat.com, eranian@google.com, gregkh@linuxfoundation.org, jolsa@redhat.com, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org, vincent.weaver@maine.edu Cc: , From: Date: Sat, 09 Apr 2016 11:32:47 -0700 Message-ID: <146022676722149@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled perf/core: Fix perf_sched_count derailment to the 4.5-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: perf-core-fix-perf_sched_count-derailment.patch and it can be found in the queue-4.5 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 927a5570855836e5d5859a80ce7e91e963545e8f Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Wed, 2 Mar 2016 13:24:14 +0200 Subject: perf/core: Fix perf_sched_count derailment From: Alexander Shishkin commit 927a5570855836e5d5859a80ce7e91e963545e8f upstream. The error path in perf_event_open() is such that asking for a sampling event on a PMU that doesn't generate interrupts will end up in dropping the perf_sched_count even though it hasn't been incremented for this event yet. Given a sufficient amount of these calls, we'll end up disabling scheduler's jump label even though we'd still have active events in the system, thereby facilitating the arrival of the infernal regions upon us. I'm fixing this by moving account_event() inside perf_event_alloc(). Signed-off-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: vince@deater.net Link: http://lkml.kernel.org/r/1456917854-29427-1-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/events/core.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8001,6 +8001,9 @@ perf_event_alloc(struct perf_event_attr } } + /* symmetric to unaccount_event() in _free_event() */ + account_event(event); + return event; err_per_task: @@ -8364,8 +8367,6 @@ SYSCALL_DEFINE5(perf_event_open, } } - account_event(event); - /* * Special case software events and allow them to be part of * any hardware group. @@ -8662,8 +8663,6 @@ perf_event_create_kernel_counter(struct /* Mark owner so we could distinguish it from user events. */ event->owner = TASK_TOMBSTONE; - account_event(event); - ctx = find_get_context(event->pmu, task, event); if (IS_ERR(ctx)) { err = PTR_ERR(ctx); Patches currently in stable-queue which might be from alexander.shishkin@linux.intel.com are queue-4.5/perf-x86-intel-add-definition-for-pt-pmi-bit.patch queue-4.5/perf-core-fix-perf_sched_count-derailment.patch