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syzkaller: WARNING in mptcp_sendmsg_frag
#444
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@cpaasch: could you please include the syzkaller log up to e a few progs before the splat itself? Side note: as a wild guess this looks unrelated to the recent changes |
There you go @pabeni :
|
the triggered warning is: /* all mptcp-level data is acked, no skbs should be present into the
* ssk write queue
*/
WARN_ON_ONCE(reuse_skb); Reviewing the code again, I think that in theory we could have a (reinjected?!?) packet in the subflow write queue and while receiving and msk level ack moving the snd_una up to snd_nxt. And that can happen while executing mptcp_sendmsg_frag(), if there are multiple established subflows, as snd_una is updated under the mptcp_data_lock. The following patch should avoid the splat: diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 990fcf53074a..2b540b3681b8 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1297,7 +1297,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
if (copy == 0) {
u64 snd_una = READ_ONCE(msk->snd_una);
- if (snd_una != msk->snd_nxt) {
+ if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {
tcp_remove_empty_skb(ssk);
return 0;
} @cpaasch: could you please give it a shot in your testbed?!? Still I'm not sure if and why exactly the above described race could happen, so a possible, alternative, debug patch could be helpful: @@ -1309,7 +1309,10 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
/* all mptcp-level data is acked, no skbs should be present into the
* ssk write queue
*/
- WARN_ON_ONCE(reuse_skb);
+ if (WARN_ON_ONCE(reuse_skb))
+ pr_warn("acked bytes %lld sent bytes %lld snd_una %lld skb seq %lld skb len %d data seq %lld subflows %d",
+ msk->bytes_acked, msk->bytes_sent, snd_una, mpext ? mpext->data_seq : -1,
+ skb->len, dfrag->data_seq + info->sent, msk->pm.subflows);
}
copy = min_t(size_t, copy, info->limit - info->sent); @cpaasch: it would be great if you could reproduce at least once the issue with the debug patch applied before testing the tentative fix, thanks! |
Sure - updating with the debug patch now. |
@pabeni :
|
Adding the fix now.. |
@pabeni - the fix resolves the issue for me. |
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 torvalds#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 warning. Reported-by: Christoph Paasch <cpaasch@apple.com> Closes: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com>
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: #444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org>
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: #444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org>
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: #444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org>
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: #444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org>
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: #444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org>
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: #444 Fixes: f70cad1 ("mptcp: stop relying on tcp_tx_skb_cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <martineau@kernel.org>
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 torvalds#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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
commit 72377ab 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 torvalds#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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
commit 72377ab 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 torvalds#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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
commit 72377ab 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 torvalds#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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
commit 72377ab 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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
commit 72377ab 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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
[ Upstream commit 72377ab ] 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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1 ("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>
BugLink: https://bugs.launchpad.net/bugs/2049417 [ Upstream commit 72377ab2d671befd6390a1d5677f5cca61235b65 ] 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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1085d1 ("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> Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com>
BugLink: https://bugs.launchpad.net/bugs/2049417 [ Upstream commit 72377ab2d671befd6390a1d5677f5cca61235b65 ] 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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1085d1 ("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> Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
BugLink: https://bugs.launchpad.net/bugs/2049417 [ Upstream commit 72377ab2d671befd6390a1d5677f5cca61235b65 ] 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: multipath-tcp/mptcp_net-next#444 Fixes: f70cad1085d1 ("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> Signed-off-by: Roxana Nicolescu <roxana.nicolescu@canonical.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
syzkaller-id: 05c7ddf5ee57b69d6d9d2cea1420e5e624c2a5a1
HEAD: 331b78e
Trace:
Kconfig:
Kconfig_k7_clean.txt
No reproducer.
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