diff mbox series

[net,2/4] mptcp: stricter state check in mptcp_worker

Message ID 20230411-upstream-net-20230411-mptcp-fixes-v1-2-ca540f3ef986@tessares.net (mailing list archive)
State Accepted
Commit d6a0443733434408f2cbd4c53fea6910599bab9e
Delegated to: Netdev Maintainers
Headers show
Series mptcp: more fixes for 6.3 | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 21 this patch: 21
netdev/cc_maintainers success CCed 8 of 8 maintainers
netdev/build_clang success Errors and warnings before: 18 this patch: 18
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 21 this patch: 21
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 8 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Matthieu Baerts April 11, 2023, 8:42 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

As reported by Christoph, the mptcp protocol can run the
worker when the relevant msk socket is in an unexpected state:

connect()
// incoming reset + fastclose
// the mptcp worker is scheduled
mptcp_disconnect()
// msk is now CLOSED
listen()
mptcp_worker()

Leading to the following splat:

divide error: 0000 [#1] PREEMPT SMP
CPU: 1 PID: 21 Comm: kworker/1:0 Not tainted 6.3.0-rc1-gde5e8fd0123c #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
Workqueue: events mptcp_worker
RIP: 0010:__tcp_select_window+0x22c/0x4b0 net/ipv4/tcp_output.c:3018
RSP: 0018:ffffc900000b3c98 EFLAGS: 00010293
RAX: 000000000000ffd7 RBX: 000000000000ffd7 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8214ce97 RDI: 0000000000000004
RBP: 000000000000ffd7 R08: 0000000000000004 R09: 0000000000010000
R10: 000000000000ffd7 R11: ffff888005afa148 R12: 000000000000ffd7
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88803ed00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000405270 CR3: 000000003011e006 CR4: 0000000000370ee0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 tcp_select_window net/ipv4/tcp_output.c:262 [inline]
 __tcp_transmit_skb+0x356/0x1280 net/ipv4/tcp_output.c:1345
 tcp_transmit_skb net/ipv4/tcp_output.c:1417 [inline]
 tcp_send_active_reset+0x13e/0x320 net/ipv4/tcp_output.c:3459
 mptcp_check_fastclose net/mptcp/protocol.c:2530 [inline]
 mptcp_worker+0x6c7/0x800 net/mptcp/protocol.c:2705
 process_one_work+0x3bd/0x950 kernel/workqueue.c:2390
 worker_thread+0x5b/0x610 kernel/workqueue.c:2537
 kthread+0x138/0x170 kernel/kthread.c:376
 ret_from_fork+0x2c/0x50 arch/x86/entry/entry_64.S:308
 </TASK>

This change addresses the issue explicitly checking for bad states
before running the mptcp worker.

Fixes: e16163b6e2b7 ("mptcp: refactor shutdown and close")
Cc: stable@vger.kernel.org
Reported-by: Christoph Paasch <cpaasch@apple.com>
Link: https://github.com/multipath-tcp/mptcp_net-next/issues/374
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Tested-by: Christoph Paasch <cpaasch@apple.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
---
 net/mptcp/protocol.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 60b23b2716c4..06c5872e3b00 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2626,7 +2626,7 @@  static void mptcp_worker(struct work_struct *work)
 
 	lock_sock(sk);
 	state = sk->sk_state;
-	if (unlikely(state == TCP_CLOSE))
+	if (unlikely((1 << state) & (TCPF_CLOSE | TCPF_LISTEN)))
 		goto unlock;
 
 	mptcp_check_data_fin_ack(sk);