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authorBaptiste Lepers <baptiste.lepers@gmail.com>2021-09-06 11:53:10 +1000
committerPeter Zijlstra <peterz@infradead.org>2021-09-15 17:49:06 +0200
commitb89a05b21f46150ac10a962aa50109250b56b03b (patch)
treee4a85375c8fbeef5edd0fc1fba90d47bc23835df /kernel/events
parent6880fa6c56601bb8ed59df6c30fd390cc5f6dd8f (diff)
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
Diffstat (limited to 'kernel/events')
-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 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;