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From: Hillf Danton <hdanton@sina.com>
To: syzbot <syzbot+f311e026553fee3459a0@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [bpf?] [net?] possible deadlock in hrtimer_run_queues
Date: Wed, 20 Mar 2024 18:55:38 +0800
Message-Id: <20240320105538.2238-1-hdanton@sina.com>
In-Reply-To: <0000000000004b02a206140b016b@google.com>
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On Tue, 19 Mar 2024 15:29:19 -0700
> syzbot found the following issue on:
> 
> HEAD commit:    ea80e3ed09ab net: ethernet: mtk_eth_soc: fix PPE hanging i..
> git tree:       net
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11c64e31180000

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git  ea80e3ed09ab

--- x/net/core/sock_map.c
+++ y/net/core/sock_map.c
@@ -932,11 +932,12 @@ static long sock_hash_delete_elem(struct
 	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
 		sock_hash_free_elem(htab, elem);
 		ret = 0;
 	}
-	spin_unlock_bh(&bucket->lock);
+	spin_unlock_irqrestore(&bucket->lock, flags);
 	return ret;
 }
 
--