Re: [syzbot] [bpf?] [net?] possible deadlock in scheduler_tick (3)

From: Edward Adam Davis
Date: Wed Mar 20 2024 - 20:23:48 EST


please test dl in scheduler_tick

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf.git master

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index 27d733c0f65e..8a21a59eb599 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -932,11 +932,12 @@ static long 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);

- spin_lock_bh(&bucket->lock);
+ 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);
@@ -944,7 +945,7 @@ static long sock_hash_delete_elem(struct bpf_map *map, void *key)
sock_hash_free_elem(htab, elem);
ret = 0;
}
- spin_unlock_bh(&bucket->lock);
+ spin_unlock_irqrestore(&bucket->lock, flags);
return ret;
}