diff options
| author | He Fengqing <[email protected]> | 2022-01-22 10:29:36 +0000 |
|---|---|---|
| committer | Alexei Starovoitov <[email protected]> | 2022-01-25 17:50:03 -0800 |
| commit | 0e3135d3bfa5dfb658145238d2bc723a8e30c3a3 (patch) | |
| tree | 3677f5921a1e98e432e54135287577bcc37d8c87 | |
| parent | 63ee956f69d8c181e5251c7ce58b84c1edec0f6a (diff) | |
bpf: Fix possible race in inc_misses_counter
It seems inc_misses_counter() suffers from same issue fixed in
the commit d979617aa84d ("bpf: Fixes possible race in update_prog_stats()
for 32bit arches"):
As it can run while interrupts are enabled, it could
be re-entered and the u64_stats syncp could be mangled.
Fixes: 9ed9e9ba2337 ("bpf: Count the number of times recursion was prevented")
Signed-off-by: He Fengqing <[email protected]>
Acked-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>
| -rw-r--r-- | kernel/bpf/trampoline.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 4b6974a195c1..5e7edf913060 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -550,11 +550,12 @@ static __always_inline u64 notrace bpf_prog_start_time(void) static void notrace inc_misses_counter(struct bpf_prog *prog) { struct bpf_prog_stats *stats; + unsigned int flags; stats = this_cpu_ptr(prog->stats); - u64_stats_update_begin(&stats->syncp); + flags = u64_stats_update_begin_irqsave(&stats->syncp); u64_stats_inc(&stats->misses); - u64_stats_update_end(&stats->syncp); + u64_stats_update_end_irqrestore(&stats->syncp, flags); } /* The logic is similar to bpf_prog_run(), but with an explicit |