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authorEric Dumazet <edumazet@google.com>2021-10-26 14:41:32 -0700
committerAlexei Starovoitov <ast@kernel.org>2021-10-27 11:13:52 -0700
commitd979617aa84d96acca44c2f5778892b4565e322f (patch)
treeff58a7ed0c96b37015fb26af06e914d4677256e7 /kernel/bpf
parentf941eadd8d6d4ee2f8c9aeab8e1da5e647533a7d (diff)
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bpf: Fixes possible race in update_prog_stats() for 32bit arches
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
Diffstat (limited to 'kernel/bpf')
-rw-r--r--kernel/bpf/trampoline.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c
index 39eaaff81953..e5963de368ed 100644
--- a/kernel/bpf/trampoline.c
+++ b/kernel/bpf/trampoline.c
@@ -586,11 +586,13 @@ 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);
}
}