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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2019-11-01 17:12:48 +0200
committerIngo Molnar <mingo@kernel.org>2019-11-13 08:16:40 +0100
commit00496fe5e09e8c8bb115540e7e3470553cd07a5c (patch)
tree728e7803f48b326150c438d85613fc695749189c /kernel
parent09f4e8f05d85bfc98fe9227e988a7c1b3ec416ec (diff)
downloadlinux-00496fe5e09e8c8bb115540e7e3470553cd07a5c.tar.bz2
perf/aux: Fix the aux_output group inheritance fix
Commit f733c6b508bc ("perf/core: Fix inheritance of aux_output groups") adds a NULL pointer dereference in case inherit_group() races with perf_release(), which causes the below crash: > BUG: kernel NULL pointer dereference, address: 000000000000010b > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 3b203b067 P4D 3b203b067 PUD 3b2040067 PMD 0 > Oops: 0000 [#1] SMP KASAN > CPU: 0 PID: 315 Comm: exclusive-group Tainted: G B 5.4.0-rc3-00181-g72e1839403cb-dirty #878 > RIP: 0010:perf_get_aux_event+0x86/0x270 > Call Trace: > ? __perf_read_group_add+0x3b0/0x3b0 > ? __kasan_check_write+0x14/0x20 > ? __perf_event_init_context+0x154/0x170 > inherit_task_group.isra.0.part.0+0x14b/0x170 > perf_event_init_task+0x296/0x4b0 Fix this by skipping over events that are getting closed, in the inheritance path. Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Fixes: f733c6b508bc ("perf/core: Fix inheritance of aux_output groups") Link: https://lkml.kernel.org/r/20191101151248.47327-1-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/events/core.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 022a34b66e60..b752bd3aa03b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11899,7 +11899,7 @@ static int inherit_group(struct perf_event *parent_event,
if (IS_ERR(child_ctr))
return PTR_ERR(child_ctr);
- if (sub->aux_event == parent_event &&
+ if (sub->aux_event == parent_event && child_ctr &&
!perf_get_aux_event(child_ctr, leader))
return -EINVAL;
}