Re: [PATCH] perf/bpf: Fix data race in __perf_event_overflow

From: Peter Zijlstra

Date: Wed Aug 12 2026 - 06:30:40 EST


On Wed, Aug 12, 2026 at 05:23:31AM +0530, Deepanshu Kartikey wrote:
> perf_event_detach_bpf_prog() writes event->prog = NULL
> under bpf_event_mutex, while __perf_event_overflow() reads
> event->prog concurrently without any lock protection. This
> causes a data race detected by KCSAN.

IIRC perf_event_free_pbf_prog() was supposed to be called after the
event is shut down, so there is no possible concurrency.