Commit-ID: a4f144ebbdf6f7807c477bce8e136047ed27321f
Gitweb: http://git.kernel.org/tip/a4f144ebbdf6f7807c477bce8e136047ed27321f
Author: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
AuthorDate: Wed, 1 Jun 2016 12:33:05 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
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 <davidcc@xxxxxxxxxx>
Reviewed-by: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Zheng <zheng.z.yan@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1464809585-66072-1-git-send-email-davidcc@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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);
}
--
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