Subject: Re: [syzbot] [bpf?] [net?] possible deadlock in ahci_single_level_irq_intr

From: Jakub Sitnicki <[email-masked]>
Date: Wed, 27 Mar 2024 21:04:14 +0100

#syz test: git://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..3692f7256dd6 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -907,6 +907,7 @@ static void sock_hash_delete_from_link(struct bpf_map *map, struct sock *sk,
 	struct bpf_shtab_elem *elem_probe, *elem = link_raw;
 	struct bpf_shtab_bucket *bucket;
 
+	WARN_ON_ONCE(irqs_disabled());
 	WARN_ON_ONCE(!rcu_read_lock_held());
 	bucket = sock_hash_select_bucket(htab, elem->hash);
 
@@ -933,6 +934,10 @@ static long sock_hash_delete_elem(struct bpf_map *map, void *key)
 	struct bpf_shtab_elem *elem;
 	int ret = -ENOENT;
 
+	/* Can't run. We don't to play nice with hardirq-safe locks. */
+	if (irqs_disabled())
+		return -EOPNOTSUPP;
+
 	hash = sock_hash_bucket_hash(key, key_size);
 	bucket = sock_hash_select_bucket(htab, hash);
 
@@ -986,6 +991,7 @@ static int sock_hash_update_common(struct bpf_map *map, void *key,
 	struct sk_psock *psock;
 	int ret;
 
+	WARN_ON_ONCE(irqs_disabled());
 	WARN_ON_ONCE(!rcu_read_lock_held());
 	if (unlikely(flags > BPF_EXIST))
 		return -EINVAL;