From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-by2nam03on0126.outbound.protection.outlook.com ([104.47.42.126]:2432 "EHLO NAM03-BY2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755428AbeDIA0z (ORCPT ); Sun, 8 Apr 2018 20:26:55 -0400 From: Sasha Levin To: "stable@vger.kernel.org" , "linux-kernel@vger.kernel.org" CC: Xin Long , "David S . Miller" , Sasha Levin Subject: [PATCH AUTOSEL for 4.9 028/293] sctp: fix recursive locking warning in sctp_do_peeloff Date: Mon, 9 Apr 2018 00:23:12 +0000 Message-ID: <20180409002239.163177-28-alexander.levin@microsoft.com> References: <20180409002239.163177-1-alexander.levin@microsoft.com> In-Reply-To: <20180409002239.163177-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Xin Long [ Upstream commit 6dfe4b97e08ec3d1a593fdaca099f0ef0a3a19e6 ] Dmitry got the following recursive locking report while running syzkaller fuzzer, the Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x2ee/0x3ef lib/dump_stack.c:52 print_deadlock_bug kernel/locking/lockdep.c:1729 [inline] check_deadlock kernel/locking/lockdep.c:1773 [inline] validate_chain kernel/locking/lockdep.c:2251 [inline] __lock_acquire+0xef2/0x3430 kernel/locking/lockdep.c:3340 lock_acquire+0x2a1/0x630 kernel/locking/lockdep.c:3755 lock_sock_nested+0xcb/0x120 net/core/sock.c:2536 lock_sock include/net/sock.h:1460 [inline] sctp_close+0xcd/0x9d0 net/sctp/socket.c:1497 inet_release+0xed/0x1c0 net/ipv4/af_inet.c:425 inet6_release+0x50/0x70 net/ipv6/af_inet6.c:432 sock_release+0x8d/0x1e0 net/socket.c:597 __sock_create+0x38b/0x870 net/socket.c:1226 sock_create+0x7f/0xa0 net/socket.c:1237 sctp_do_peeloff+0x1a2/0x440 net/sctp/socket.c:4879 sctp_getsockopt_peeloff net/sctp/socket.c:4914 [inline] sctp_getsockopt+0x111a/0x67e0 net/sctp/socket.c:6628 sock_common_getsockopt+0x95/0xd0 net/core/sock.c:2690 SYSC_getsockopt net/socket.c:1817 [inline] SyS_getsockopt+0x240/0x380 net/socket.c:1799 entry_SYSCALL_64_fastpath+0x1f/0xc2 This warning is caused by the lock held by sctp_getsockopt() is on one socket, while the other lock that sctp_close() is getting later is on the newly created (which failed) socket during peeloff operation. This patch is to avoid this warning by use lock_sock with subclass SINGLE_DEPTH_NESTING as Wang Cong and Marcelo's suggestion. Reported-by: Dmitry Vyukov Suggested-by: Marcelo Ricardo Leitner Suggested-by: Cong Wang Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/sctp/socket.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 8cdd6bbe2efa..172465b7c0f4 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -1519,7 +1519,7 @@ static void sctp_close(struct sock *sk, long timeout) =20 pr_debug("%s: sk:%p, timeout:%ld\n", __func__, sk, timeout); =20 - lock_sock(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); sk->sk_shutdown =3D SHUTDOWN_MASK; sk->sk_state =3D SCTP_SS_CLOSING; =20 @@ -1569,7 +1569,7 @@ static void sctp_close(struct sock *sk, long timeout) * held and that should be grabbed before socket lock. */ spin_lock_bh(&net->sctp.addr_wq_lock); - bh_lock_sock(sk); + bh_lock_sock_nested(sk); =20 /* Hold the sock, since sk_common_release() will put sock_put() * and we have just a little more cleanup. --=20 2.15.1