Paolo Abeni 90918ef995 mptcp: more conservative check for zero probes ... [ Upstream commit 72377ab2d6 ] Christoph reported that the MPTCP protocol can find the subflow-level write queue unexpectedly not empty while crafting a zero-window probe, hitting a warning: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 188 at net/mptcp/protocol.c:1312 mptcp_sendmsg_frag+0xc06/0xe70 Modules linked in: CPU: 0 PID: 188 Comm: kworker/0:2 Not tainted 6.6.0-rc2-g1176aa719d7a #47 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014 Workqueue: events mptcp_worker RIP: 0010:mptcp_sendmsg_frag+0xc06/0xe70 net/mptcp/protocol.c:1312 RAX: 47d0530de347ff6a RBX: 47d0530de347ff6b RCX: ffff8881015d3c00 RDX: ffff8881015d3c00 RSI: 47d0530de347ff6b RDI: 47d0530de347ff6b RBP: 47d0530de347ff6b R08: ffffffff8243c6a8 R09: ffffffff82042d9c R10: 0000000000000002 R11: ffffffff82056850 R12: ffff88812a13d580 R13: 0000000000000001 R14: ffff88812b375e50 R15: ffff88812bbf3200 FS: 0000000000000000(0000) GS:ffff88813bc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000695118 CR3: 0000000115dfc001 CR4: 0000000000170ef0 Call Trace: <TASK> __subflow_push_pending+0xa4/0x420 net/mptcp/protocol.c:1545 __mptcp_push_pending+0x128/0x3b0 net/mptcp/protocol.c:1614 mptcp_release_cb+0x218/0x5b0 net/mptcp/protocol.c:3391 release_sock+0xf6/0x100 net/core/sock.c:3521 mptcp_worker+0x6e8/0x8f0 net/mptcp/protocol.c:2746 process_scheduled_works+0x341/0x690 kernel/workqueue.c:2630 worker_thread+0x3a7/0x610 kernel/workqueue.c:2784 kthread+0x143/0x180 kernel/kthread.c:388 ret_from_fork+0x4d/0x60 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:304 </TASK> The root cause of the issue is that expectations are wrong: e.g. due to MPTCP-level re-injection we can hit the critical condition. Explicitly avoid the zero-window probe when the subflow write queue is not empty and drop the related warnings. Reported-by: Christoph Paasch <cpaasch@apple.com> Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/444 Fixes: f70cad1085 ("mptcp: stop relying on tcp_tx_skb_cache") Cc: stable@vger.kernel.org Reviewed-by: Mat Martineau <martineau@kernel.org> Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Mat Martineau <martineau@kernel.org> Link: https://lore.kernel.org/r/20231018-send-net-20231018-v1-3-17ecb002e41d@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>		2023-11-08 17:26:35 +01:00
..
Kconfig	kunit: mptcp: adhere to KUNIT formatting standard	2021-04-16 17:10:40 -07:00
Makefile	kunit: mptcp: adhere to KUNIT formatting standard	2021-04-16 17:10:40 -07:00
crypto.c	kunit: mptcp: adhere to KUNIT formatting standard	2021-04-16 17:10:40 -07:00
crypto_test.c	mptcp: move crypto test to KUNIT	2020-06-26 16:21:39 -07:00
ctrl.c	mptcp: faster active backup recovery	2021-08-14 11:37:25 +01:00
diag.c	mptcp: allow dumping subflow context to userspace	2020-03-29 22:14:48 -07:00
mib.c	mptcp: add mibs counter for ignored incoming options	2022-03-02 11:47:53 +01:00
mib.h	mptcp: add mibs counter for ignored incoming options	2022-03-02 11:47:53 +01:00
mptcp_diag.c	mptcp: don't return sockets in foreign netns	2021-09-24 10:51:36 +01:00
options.c	mptcp: use mptcp_schedule_work instead of open-coding it	2023-04-20 12:13:56 +02:00
pm.c	mptcp: add mibs counter for ignored incoming options	2022-03-02 11:47:53 +01:00
pm_netlink.c	mptcp: fix lockdep false positive in mptcp_pm_nl_create_listen_socket()	2023-03-22 13:31:35 +01:00
protocol.c	mptcp: more conservative check for zero probes	2023-11-08 17:26:35 +01:00
protocol.h	mptcp: Do TCP fallback on early DSS checksum failure	2022-05-25 14:42:07 +02:00
sockopt.c	mptcp: remove tcp ulp setsockopt support	2021-12-22 09:32:43 +01:00
subflow.c	mptcp: consolidate fallback and non fallback state machine	2023-07-05 18:25:04 +01:00
syncookies.c	mptcp: don't return sockets in foreign netns	2021-09-24 10:51:36 +01:00
token.c	mptcp: don't return sockets in foreign netns	2021-09-24 10:51:36 +01:00
token_test.c	mptcp: don't return sockets in foreign netns	2021-09-24 10:51:36 +01:00