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| author | Baptiste Lepers <baptiste.lepers@gmail.com> | 2021-09-06 04:53:10 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-22 12:45:33 +0300 |
| commit | a2d09569f1e3c148921ffefd2e5e0298e7c51022 (patch) | |
| tree | b08582f9281c1318e5bf2892e870df105c97fd60 | |
| parent | adc7f7c53219f8e0430cfba81a0b7cfc23bb7e68 (diff) | |
| download | linux-a2d09569f1e3c148921ffefd2e5e0298e7c51022.tar.xz | |
events: Reuse value read using READ_ONCE instead of re-reading it
commit b89a05b21f46150ac10a962aa50109250b56b03b upstream.
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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 1aa094c5dedb..236e7900e3fc 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8435,7 +8435,7 @@ static void perf_event_addr_filters_apply(struct perf_event *event) if (!ifh->nr_file_filters) return; - mm = get_task_mm(event->ctx->task); + mm = get_task_mm(task); if (!mm) goto restart; |