From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E60531C6FFE; Wed, 5 Mar 2025 17:57:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197465; cv=none; b=qujX+iz4sOgY0mJ+wcFIgb8ebhG1Kob4Ykc5qwJHVL6Zy9x74VJZQEfmImvPsQihyrb4QSHXXwndSeXqJFTDhTkEWulBsAXMCtc7uP78DlteyL8zRMzSPNetAoZJF2qhM+3KR66IoD9QBYz16od7HD8eXyzs/Kj5TyBfWpX8N30= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741197465; c=relaxed/simple; bh=XjNGaDoUfnDNTGj/2vgp3XXPahCc1wfaiTAfAdtCjU0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mqc9vYjQMocJb/Cu/023nJaYmJiSpR9qaGyFuEjqjcnpYypeoiu6e2LCXTkgchLLizQd06szv9FNEZU2uvUNs3Xckx+2RU93TkFoWtbCCj1vrc76q1QDVDsmMJvQX0ClZPidhLHEiP5dv6dkRXDhTN2mL/2yTcF7uibAtCq7yPI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uXYSsk0e; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="uXYSsk0e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 76629C4CED1; Wed, 5 Mar 2025 17:57:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741197464; bh=XjNGaDoUfnDNTGj/2vgp3XXPahCc1wfaiTAfAdtCjU0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uXYSsk0eymSGDZTCOViM1vnknwLU1kvyzbsw28TJNCcWNbGqPUgwdQeCS1hwQjBw+ Hp8pb8XROOrdHa+eZpe9IaL4GT17baAoR/wnBVFO4Fq+dwFUsvC+h+/Dnc5rsft2Z1 Pm1q3uouEptllg8MA3vY61c6nB4a7mLjXrZKNSpQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+cd3ce3d03a3393ae9700@syzkaller.appspotmail.com, Paolo Abeni , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 6.1 164/176] mptcp: always handle address removal under msk socket lock Date: Wed, 5 Mar 2025 18:48:53 +0100 Message-ID: <20250305174512.028104828@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305174505.437358097@linuxfoundation.org> References: <20250305174505.437358097@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paolo Abeni commit f865c24bc55158313d5779fc81116023a6940ca3 upstream. Syzkaller reported a lockdep splat in the PM control path: WARNING: CPU: 0 PID: 6693 at ./include/net/sock.h:1711 sock_owned_by_me include/net/sock.h:1711 [inline] WARNING: CPU: 0 PID: 6693 at ./include/net/sock.h:1711 msk_owned_by_me net/mptcp/protocol.h:363 [inline] WARNING: CPU: 0 PID: 6693 at ./include/net/sock.h:1711 mptcp_pm_nl_addr_send_ack+0x57c/0x610 net/mptcp/pm_netlink.c:788 Modules linked in: CPU: 0 UID: 0 PID: 6693 Comm: syz.0.205 Not tainted 6.14.0-rc2-syzkaller-00303-gad1b832bf1cf #0 Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024 RIP: 0010:sock_owned_by_me include/net/sock.h:1711 [inline] RIP: 0010:msk_owned_by_me net/mptcp/protocol.h:363 [inline] RIP: 0010:mptcp_pm_nl_addr_send_ack+0x57c/0x610 net/mptcp/pm_netlink.c:788 Code: 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc e8 ca 7b d3 f5 eb b9 e8 c3 7b d3 f5 90 0f 0b 90 e9 dd fb ff ff e8 b5 7b d3 f5 90 <0f> 0b 90 e9 3e fb ff ff 44 89 f1 80 e1 07 38 c1 0f 8c eb fb ff ff RSP: 0000:ffffc900034f6f60 EFLAGS: 00010283 RAX: ffffffff8bee3c2b RBX: 0000000000000001 RCX: 0000000000080000 RDX: ffffc90004d42000 RSI: 000000000000a407 RDI: 000000000000a408 RBP: ffffc900034f7030 R08: ffffffff8bee37f6 R09: 0100000000000000 R10: dffffc0000000000 R11: ffffed100bcc62e4 R12: ffff88805e6316e0 R13: ffff88805e630c00 R14: dffffc0000000000 R15: ffff88805e630c00 FS: 00007f7e9a7e96c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2fd18ff8 CR3: 0000000032c24000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: mptcp_pm_remove_addr+0x103/0x1d0 net/mptcp/pm.c:59 mptcp_pm_remove_anno_addr+0x1f4/0x2f0 net/mptcp/pm_netlink.c:1486 mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_netlink.c:1518 [inline] mptcp_pm_nl_del_addr_doit+0x118d/0x1af0 net/mptcp/pm_netlink.c:1629 genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline] genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline] genl_rcv_msg+0xb1f/0xec0 net/netlink/genetlink.c:1210 netlink_rcv_skb+0x206/0x480 net/netlink/af_netlink.c:2543 genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219 netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline] netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1348 netlink_sendmsg+0x8de/0xcb0 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg+0x221/0x270 net/socket.c:733 ____sys_sendmsg+0x53a/0x860 net/socket.c:2573 ___sys_sendmsg net/socket.c:2627 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2659 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7e9998cde9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f7e9a7e9038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f7e99ba5fa0 RCX: 00007f7e9998cde9 RDX: 000000002000c094 RSI: 0000400000000000 RDI: 0000000000000007 RBP: 00007f7e99a0e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f7e99ba5fa0 R15: 00007fff49231088 Indeed the PM can try to send a RM_ADDR over a msk without acquiring first the msk socket lock. The bugged code-path comes from an early optimization: when there are no subflows, the PM should (usually) not send RM_ADDR notifications. The above statement is incorrect, as without locks another process could concurrent create a new subflow and cause the RM_ADDR generation. Additionally the supposed optimization is not very effective even performance-wise, as most mptcp sockets should have at least one subflow: the MPC one. Address the issue removing the buggy code path, the existing "slow-path" will handle correctly even the edge case. Fixes: b6c08380860b ("mptcp: remove addr and subflow in PM netlink") Cc: stable@vger.kernel.org Reported-by: syzbot+cd3ce3d03a3393ae9700@syzkaller.appspotmail.com Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/546 Signed-off-by: Paolo Abeni Reviewed-by: Matthieu Baerts (NGI0) Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250224-net-mptcp-misc-fixes-v1-1-f550f636b435@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/mptcp/pm_netlink.c | 5 ----- 1 file changed, 5 deletions(-) --- a/net/mptcp/pm_netlink.c +++ b/net/mptcp/pm_netlink.c @@ -1554,11 +1554,6 @@ static int mptcp_nl_remove_subflow_and_s if (mptcp_pm_is_userspace(msk)) goto next; - if (list_empty(&msk->conn_list)) { - mptcp_pm_remove_anno_addr(msk, addr, false); - goto next; - } - lock_sock(sk); remove_subflow = lookup_subflow_by_saddr(&msk->conn_list, addr); mptcp_pm_remove_anno_addr(msk, addr, remove_subflow &&