From c5b96789575b670b1e776071bb243e0ed3d3abaa Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 4 Nov 2024 14:39:22 +0100 Subject: [PATCH] perf/bpf: Robustify perf_event_free_bpf_prog() Ensure perf_event_free_bpf_prog() is safe to call a second time; notably without making any references to event->pmu when there is no prog left. Note: perf_event_detach_bpf_prog() might leave a stale event->prog Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Ingo Molnar Reviewed-by: Ravi Bangoria Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Andrii Nakryiko Link: https://lore.kernel.org/r/20241104135518.978956692@infradead.org --- kernel/events/core.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/events/core.c b/kernel/events/core.c index 525c64ee7925b..ab4e497087daf 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10905,6 +10905,9 @@ int perf_event_set_bpf_prog(struct perf_event *event, struct bpf_prog *prog, void perf_event_free_bpf_prog(struct perf_event *event) { + if (!event->prog) + return; + if (!perf_event_is_tracing(event)) { perf_event_free_bpf_handler(event); return; -- 2.47.2