From: Eric Dumazet edumazet@google.com
[ 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@google.com Signed-off-by: Alexei Starovoitov ast@kernel.org Link: https://lore.kernel.org/bpf/20211026214133.3114279-3-eric.dumazet@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/trampoline.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
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); } }