Commit-ID: a4f144ebbdf6f7807c477bce8e136047ed27321f Gitweb: http://git.kernel.org/tip/a4f144ebbdf6f7807c477bce8e136047ed27321f Author: David Carrillo-Cisneros <davi...@google.com> AuthorDate: Wed, 1 Jun 2016 12:33:05 -0700 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Wed, 8 Jun 2016 09:18:45 +0200
perf/core: Fix crash due to account/unaccount_sb_event() inconsistency unaccount_pmu_sb_event() did not check for attributes in event->attr before calling detach_sb_event(), while account_pmu_event() did. This caused NULL pointer reference in cgroup events that did not have any of the attributes checked by account_pmu_event(). To trigger the bug just wait for a cgroup event to terminate, e.g.: $ mkdir /dev/cgroup/devices/test $ perf stat -e cycles -a -G test sleep 0 ... see crash ... Signed-off-by: David Carrillo-Cisneros <davi...@google.com> Reviewed-by: Stephane Eranian <eran...@google.com> Cc: Alexander Shishkin <alexander.shish...@linux.intel.com> Cc: Arnaldo Carvalho de Melo <a...@redhat.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Kan Liang <kan.li...@intel.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Zheng <zheng.z....@intel.com> Link: http://lkml.kernel.org/r/1464809585-66072-1-git-send-email-davi...@google.com Signed-off-by: Ingo Molnar <mi...@kernel.org> --- kernel/events/core.c | 34 ++++++++++++++++++---------------- 1 file changed, 18 insertions(+), 16 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 5d48306..ae081a1 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3682,15 +3682,28 @@ static void detach_sb_event(struct perf_event *event) raw_spin_unlock(&pel->lock); } -static void unaccount_pmu_sb_event(struct perf_event *event) +static bool is_sb_event(struct perf_event *event) { + struct perf_event_attr *attr = &event->attr; + if (event->parent) - return; + return false; if (event->attach_state & PERF_ATTACH_TASK) - return; + return false; - detach_sb_event(event); + if (attr->mmap || attr->mmap_data || attr->mmap2 || + attr->comm || attr->comm_exec || + attr->task || + attr->context_switch) + return true; + return false; +} + +static void unaccount_pmu_sb_event(struct perf_event *event) +{ + if (is_sb_event(event)) + detach_sb_event(event); } static void unaccount_event_cpu(struct perf_event *event, int cpu) @@ -8666,18 +8679,7 @@ static void attach_sb_event(struct perf_event *event) */ static void account_pmu_sb_event(struct perf_event *event) { - struct perf_event_attr *attr = &event->attr; - - if (event->parent) - return; - - if (event->attach_state & PERF_ATTACH_TASK) - return; - - if (attr->mmap || attr->mmap_data || attr->mmap2 || - attr->comm || attr->comm_exec || - attr->task || - attr->context_switch) + if (is_sb_event(event)) attach_sb_event(event); }
