This is a note to let you know that I've just added the patch titled bpf: Fixes possible race in update_prog_stats() for 32bit arches to the 5.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: bpf-fixes-possible-race-in-update_prog_stats-for-32b.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit eabebec0918b4cf32f988086be213f965a63f822 Author: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Tue Oct 26 14:41:32 2021 -0700 bpf: Fixes possible race in update_prog_stats() for 32bit arches [ Upstream commit d979617aa84d96acca44c2f5778892b4565e322f ] It seems update_prog_stats() suffers from same issue fixed in the prior patch: As it can run while interrupts are enabled, it could be re-entered and the u64_stats syncp could be mangled. Fixes: fec56f5890d9 ("bpf: Introduce BPF trampoline") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx> Link: https://lore.kernel.org/bpf/20211026214133.3114279-3-eric.dumazet@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 28a3630c48ee1..9587e5ebddaa3 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -579,11 +579,13 @@ static void notrace update_prog_stats(struct bpf_prog *prog, * Hence check that 'start' is valid. */ start > NO_START_TIME) { + unsigned long flags; + stats = this_cpu_ptr(prog->stats); - u64_stats_update_begin(&stats->syncp); + flags = u64_stats_update_begin_irqsave(&stats->syncp); stats->cnt++; stats->nsecs += sched_clock() - start; - u64_stats_update_end(&stats->syncp); + u64_stats_update_end_irqrestore(&stats->syncp, flags); } }