diff options
| author | Baptiste Lepers <baptiste.lepers@gmail.com> | 2021-09-06 11:53:10 +1000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-22 12:26:41 +0200 |
| commit | 172749c879f5302ae4c580f2faec5b948e71cc47 (patch) | |
| tree | 0507f5c4f73162190d2117539de86dcf5c6a6bd4 /kernel | |
| parent | cd78d9c9968f5ed8c044794e6a2612332f11cd53 (diff) | |
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>
Diffstat (limited to 'kernel')
| -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 2f848123cdae..1993a741d2dc 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -9259,7 +9259,7 @@ 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; |