From: Eric Dumazet Date: Tue, 26 Oct 2021 21:41:32 +0000 (-0700) Subject: bpf: Fixes possible race in update_prog_stats() for 32bit arches X-Git-Tag: v5.14.19~338 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=00da55838d50faf1856db7bfc423a5292ac7476a;p=thirdparty%2Fkernel%2Fstable.git 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 Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211026214133.3114279-3-eric.dumazet@gmail.com Signed-off-by: Sasha Levin --- 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); } }