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| author | Peter Zijlstra <peterz@infradead.org> | 2016-01-27 21:59:04 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-01-29 08:35:24 +0100 |
| commit | 828b6f0e26170938d617e99a17177453be4d77a3 (patch) | |
| tree | a2e8b41d38805adf84d906bfca4d959d84ba6bee /kernel | |
| parent | perf/x86: De-obfuscate code (diff) | |
| download | linux-828b6f0e26170938d617e99a17177453be4d77a3.tar.xz linux-828b6f0e26170938d617e99a17177453be4d77a3.zip | |
perf: Fix NULL deref
Dan reported:
1229 if (ctx->task == TASK_TOMBSTONE ||
1230 !atomic_inc_not_zero(&ctx->refcount)) {
1231 raw_spin_unlock(&ctx->lock);
1232 ctx = NULL;
^^^^^^^^^^
ctx is NULL.
1233 }
1234
1235 WARN_ON_ONCE(ctx->task != task);
^^^^^^^^^^^^^^^^^
The patch adds a NULL dereference.
Reported-by: Dan Carpenter <dan.carpenter@oracle.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: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 63b6da39bb38 ("perf: Fix perf_event_exit_task() race")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1d243fadfd12..fe97f95f204e 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1230,9 +1230,9 @@ retry: !atomic_inc_not_zero(&ctx->refcount)) { raw_spin_unlock(&ctx->lock); ctx = NULL; + } else { + WARN_ON_ONCE(ctx->task != task); } - - WARN_ON_ONCE(ctx->task != task); } rcu_read_unlock(); if (!ctx) |