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| author | Baptiste Lepers <baptiste.lepers@gmail.com> | 2021-09-06 11:53:10 +1000 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-09-15 17:49:06 +0200 |
| commit | b89a05b21f46150ac10a962aa50109250b56b03b (patch) | |
| tree | e4a85375c8fbeef5edd0fc1fba90d47bc23835df | |
| parent | 6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff) | |
| download | linux-b89a05b21f46150ac10a962aa50109250b56b03b.tar.gz linux-b89a05b21f46150ac10a962aa50109250b56b03b.tar.bz2 linux-b89a05b21f46150ac10a962aa50109250b56b03b.zip | |
events: Reuse value read using READ_ONCE instead of re-reading it
In perf_event_addr_filters_apply, the task associated with
the event (event->ctx->task) is read using READ_ONCE at the beginning
of the function, checked, and then re-read from event->ctx->task,
voiding all guarantees of the checks. Reuse the value that was read by
READ_ONCE to ensure the consistency of the task struct throughout the
function.
Fixes: 375637bc52495 ("perf/core: Introduce address range filtering")
Signed-off-by: Baptiste Lepers <baptiste.lepers@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210906015310.12802-1-baptiste.lepers@gmail.com
| -rw-r--r-- | kernel/events/core.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 744e8726c5b2..0c000cb01eeb 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10193,7 +10193,7 @@ static void perf_event_addr_filters_apply(struct perf_event *event) return; if (ifh->nr_file_filters) { - mm = get_task_mm(event->ctx->task); + mm = get_task_mm(task); if (!mm) goto restart; |