6.6-stable review patch. If anyone has any objections, please let me know.
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From: Hou Tao houtao1@huawei.com
[ Upstream commit d4965578267e2e81f67c86e2608481e77e9c8569 ]
bpf_map_lookup_percpu_elem() helper is also available for sleepable bpf program. When BPF JIT is disabled or under 32-bit host, bpf_map_lookup_percpu_elem() will not be inlined. Using it in a sleepable bpf program will trigger the warning in bpf_map_lookup_percpu_elem(), because the bpf program only holds rcu_read_lock_trace lock. Therefore, add the missed check.
Reported-by: syzbot+dce5aae19ae4d6399986@syzkaller.appspotmail.com Closes: https://lore.kernel.org/bpf/000000000000176a130617420310@google.com/ Signed-off-by: Hou Tao houtao1@huawei.com Link: https://lore.kernel.org/r/20250526062534.1105938-1-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/bpf/helpers.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 41d62405c8521..8f0b62b04deeb 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -128,7 +128,8 @@ const struct bpf_func_proto bpf_map_peek_elem_proto = {
BPF_CALL_3(bpf_map_lookup_percpu_elem, struct bpf_map *, map, void *, key, u32, cpu) { - WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_bh_held()); + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held() && + !rcu_read_lock_bh_held()); return (unsigned long) map->ops->map_lookup_percpu_elem(map, key, cpu); }