Paolo Abeni d4ae85b883 mptcp: more conservative check for zero probes ... commit 72377ab2d6 upstream. 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-10-25 12:03:04 +02:00
..
bpf.c	bpf: Add bpf_skc_to_mptcp_sock_proto	2022-05-20 15:29:00 -07:00
crypto.c
crypto_test.c
ctrl.c	mptcp: Add a per-namespace sysctl to set the default path manager type	2022-04-29 17:25:14 -07:00
diag.c
Kconfig
Makefile	Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next	2022-05-23 16:07:14 -07:00
mib.c	mptcp: add more offered MIBs counter	2022-05-05 19:00:16 -07:00
mib.h	mptcp: add more offered MIBs counter	2022-05-05 19:00:16 -07:00
mptcp_diag.c	tcp: Access &tcp_hashinfo via net.	2022-09-20 10:21:49 -07:00
options.c	mptcp: fix bogus receive window shrinkage with multiple subflows	2023-10-06 14:57:00 +02:00
pm.c	mptcp: update userspace pm infos	2023-06-14 11:15:27 +02:00
pm_netlink.c	mptcp: annotate lockless accesses to sk->sk_err	2023-10-10 22:00:34 +02:00
pm_userspace.c	mptcp: userspace pm allow creating id 0 subflow	2023-10-10 22:00:38 +02:00
protocol.c	mptcp: more conservative check for zero probes	2023-10-25 12:03:04 +02:00
protocol.h	mptcp: fix delegated action races	2023-10-19 23:08:49 +02:00
sockopt.c	net: annotate data-races around sk->sk_mark	2023-08-11 12:08:14 +02:00
subflow.c	mptcp: fix delegated action races	2023-10-19 23:08:49 +02:00
syncookies.c	mptcp: don't return sockets in foreign netns	2021-09-24 10:51:36 +01:00
token.c	mptcp: full disconnect implementation	2022-01-07 11:27:06 +00:00
token_test.c	mptcp: don't return sockets in foreign netns	2021-09-24 10:51:36 +01:00