From: Eric Dumazet <edumazet@google.com>
Date: Fri, 6 Sep 2024 15:44:49 +0000 (+0000)
Subject: sock_map: Add a cond_resched() in sock_hash_free()
X-Git-Tag: v6.6.54~470
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=80bd490ac0a3b662a489e17d8eedeb1e905a3d40;p=thirdparty%2Fkernel%2Fstable.git

sock_map: Add a cond_resched() in sock_hash_free()

[ Upstream commit b1339be951ad31947ae19bc25cb08769bf255100 ]

Several syzbot soft lockup reports all have in common sock_hash_free()

If a map with a large number of buckets is destroyed, we need to yield
the cpu when needed.

Fixes: 75e68e5bf2c7 ("bpf, sockhash: Synchronize delete from bucket list on map free")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20240906154449.3742932-1-edumazet@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/net/core/sock_map.c b/net/core/sock_map.c
index a37143d181f95..2afac40bb83ca 100644
--- a/net/core/sock_map.c
+++ b/net/core/sock_map.c
@@ -1171,6 +1171,7 @@ static void sock_hash_free(struct bpf_map *map)
 			sock_put(elem->sk);
 			sock_hash_free_elem(htab, elem);
 		}
+		cond_resched();
 	}
 
 	/* wait for psock readers accessing its map link */