From: Xin Liu liuxin350@huawei.com
[ Upstream commit ed17aa92dc56b6d8883e4b7a8f1c6fbf5ed6cd29 ]
When huang uses sched_switch tracepoint, the tracepoint does only one thing in the mounted ebpf program, which deletes the fixed elements in sockhash ([0])
It seems that elements in sockhash are rarely actively deleted by users or ebpf program. Therefore, we do not pay much attention to their deletion. Compared with hash maps, sockhash only provides spin_lock_bh protection. This causes it to appear to have self-locking behavior in the interrupt context.
[0]:https://lore.kernel.org/all/CABcoxUayum5oOqFMMqAeWuS8+EzojquSOSyDA3J_2omY=2E...
Reported-by: Hsin-Wei Hung hsinweih@uci.edu Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Xin Liu liuxin350@huawei.com Acked-by: John Fastabend john.fastabend@gmail.com Link: https://lore.kernel.org/r/20230406122622.109978-1-liuxin350@huawei.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/core/sock_map.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/net/core/sock_map.c b/net/core/sock_map.c index a68a7290a3b2b..2408965e5c7b6 100644 --- a/net/core/sock_map.c +++ b/net/core/sock_map.c @@ -414,8 +414,9 @@ static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test, { struct sock *sk; int err = 0; + unsigned long flags;
- raw_spin_lock_bh(&stab->lock); + raw_spin_lock_irqsave(&stab->lock, flags); sk = *psk; if (!sk_test || sk_test == sk) sk = xchg(psk, NULL); @@ -425,7 +426,7 @@ static int __sock_map_delete(struct bpf_stab *stab, struct sock *sk_test, else err = -EINVAL;
- raw_spin_unlock_bh(&stab->lock); + raw_spin_unlock_irqrestore(&stab->lock, flags); return err; }
@@ -923,11 +924,12 @@ static int sock_hash_delete_elem(struct bpf_map *map, void *key) struct bpf_shtab_bucket *bucket; struct bpf_shtab_elem *elem; int ret = -ENOENT; + unsigned long flags;
hash = sock_hash_bucket_hash(key, key_size); bucket = sock_hash_select_bucket(htab, hash);
- raw_spin_lock_bh(&bucket->lock); + raw_spin_lock_irqsave(&bucket->lock, flags); elem = sock_hash_lookup_elem_raw(&bucket->head, hash, key, key_size); if (elem) { hlist_del_rcu(&elem->node); @@ -935,7 +937,7 @@ static int sock_hash_delete_elem(struct bpf_map *map, void *key) sock_hash_free_elem(htab, elem); ret = 0; } - raw_spin_unlock_bh(&bucket->lock); + raw_spin_unlock_irqrestore(&bucket->lock, flags); return ret; }