| Message ID | e8371ec8065e09317dcf7d7aabc6c54e63634bbb.1737222305.git.pabeni@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [mptcp-net] mptcp: handle fastopen disconnect correctly | expand |
| Context | Check | Description |
|---|---|---|
| matttbe/build | success | Build and static analysis OK |
| matttbe/checkpatch | warning | total: 0 errors, 1 warnings, 0 checks, 11 lines checked |
| matttbe/shellcheck | success | MPTCP selftests files have not been modified |
| matttbe/KVM_Validation__normal | success | Success! ✅ |
| matttbe/KVM_Validation__debug | success | Success! ✅ |
| matttbe/KVM_Validation__btf-normal__only_bpftest_all_ | success | Success! ✅ |
| matttbe/KVM_Validation__btf-debug__only_bpftest_all_ | success | Success! ✅ |
Hi Paolo,
Thank you for your modifications, that's great!
Our CI did some validations and here is its report:
- KVM Validation: normal: Success! ✅
- KVM Validation: debug: Success! ✅
- KVM Validation: btf-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/12846236981
Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/de1825fac5c2
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=926678
If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:
$ cd [kernel source code]
$ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
--pull always mptcp/mptcp-upstream-virtme-docker:latest \
auto-normal
For more details:
https://github.com/multipath-tcp/mptcp-upstream-virtme-docker
Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)
Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)
Hi Paolo, On 18/01/2025 18:46, Paolo Abeni wrote: > Syzbot was able to trigger a data stream corruption: (...) > The root cause is the bad handling of disconnect() generated > internally by the MPTCP protocol in case of connect FASTOPEN > errors. > > Address the issue increasing the socket disconnect counter even > on such a case, to allow other threads waiting on the same socket > lock to properly error out. Thank you for having looked and fixed this! > Reported-by: syzbot+ebc0b8ae5d3590b2c074@syzkaller.appspotmail.com > Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/537 > Fixes: c2b2ae3925b6 ("mptcp: handle correctly disconnect() failures") > Tested-by: syzbot+ebc0b8ae5d3590b2c074@syzkaller.appspotmail.com > Signed-off-by: Paolo Abeni <pabeni@redhat.com> > --- > net/mptcp/protocol.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c > index 1b2e7cbb577f..f910e840aa8f 100644 > --- a/net/mptcp/protocol.c > +++ b/net/mptcp/protocol.c > @@ -1767,8 +1767,10 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, > * see mptcp_disconnect(). > * Attempt it again outside the problematic scope. > */ > - if (!mptcp_disconnect(sk, 0)) > + if (!mptcp_disconnect(sk, 0)) { > + sk->sk_disconnects++; I guess it makes sense to have something similar to what is done in: net/ipv4/af_inet.c:__inet_stream_connect() Reviewed-by: Matthieu Baerts (NGI0) <matttbe@kernel.org> > sk->sk_socket->state = SS_UNCONNECTED; > + } > } > inet_clear_bit(DEFER_CONNECT, sk); > Cheers, Matt
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 1b2e7cbb577f..f910e840aa8f 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1767,8 +1767,10 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, * see mptcp_disconnect(). * Attempt it again outside the problematic scope. */ - if (!mptcp_disconnect(sk, 0)) + if (!mptcp_disconnect(sk, 0)) { + sk->sk_disconnects++; sk->sk_socket->state = SS_UNCONNECTED; + } } inet_clear_bit(DEFER_CONNECT, sk);
Syzbot was able to trigger a data stream corruption: WARNING: CPU: 0 PID: 9846 at net/mptcp/protocol.c:1024 __mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024 Modules linked in: CPU: 0 UID: 0 PID: 9846 Comm: syz-executor351 Not tainted 6.13.0-rc2-syzkaller-00059-g00a5acdbf398 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024 RIP: 0010:__mptcp_clean_una+0xddb/0xff0 net/mptcp/protocol.c:1024 Code: fa ff ff 48 8b 4c 24 18 80 e1 07 fe c1 38 c1 0f 8c 8e fa ff ff 48 8b 7c 24 18 e8 e0 db 54 f6 e9 7f fa ff ff e8 e6 80 ee f5 90 <0f> 0b 90 4c 8b 6c 24 40 4d 89 f4 e9 04 f5 ff ff 44 89 f1 80 e1 07 RSP: 0018:ffffc9000c0cf400 EFLAGS: 00010293 RAX: ffffffff8bb0dd5a RBX: ffff888033f5d230 RCX: ffff888059ce8000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffc9000c0cf518 R08: ffffffff8bb0d1dd R09: 1ffff110170c8928 R10: dffffc0000000000 R11: ffffed10170c8929 R12: 0000000000000000 R13: ffff888033f5d220 R14: dffffc0000000000 R15: ffff8880592b8000 FS: 00007f6e866496c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6e86f491a0 CR3: 00000000310e6000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> __mptcp_clean_una_wakeup+0x7f/0x2d0 net/mptcp/protocol.c:1074 mptcp_release_cb+0x7cb/0xb30 net/mptcp/protocol.c:3493 release_sock+0x1aa/0x1f0 net/core/sock.c:3640 inet_wait_for_connect net/ipv4/af_inet.c:609 [inline] __inet_stream_connect+0x8bd/0xf30 net/ipv4/af_inet.c:703 mptcp_sendmsg_fastopen+0x2a2/0x530 net/mptcp/protocol.c:1755 mptcp_sendmsg+0x1884/0x1b10 net/mptcp/protocol.c:1830 sock_sendmsg_nosec net/socket.c:711 [inline] __sock_sendmsg+0x1a6/0x270 net/socket.c:726 ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583 ___sys_sendmsg net/socket.c:2637 [inline] __sys_sendmsg+0x269/0x350 net/socket.c:2669 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: 0033:0x7f6e86ebfe69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 1f 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f6e86649168 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f6e86f491b8 RCX: 00007f6e86ebfe69 RDX: 0000000030004001 RSI: 0000000020000080 RDI: 0000000000000003 RBP: 00007f6e86f491b0 R08: 00007f6e866496c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6e86f491bc R13: 000000000000006e R14: 00007ffe445d9420 R15: 00007ffe445d9508 </TASK> The root cause is the bad handling of disconnect() generated internally by the MPTCP protocol in case of connect FASTOPEN errors. Address the issue increasing the socket disconnect counter even on such a case, to allow other threads waiting on the same socket lock to properly error out. Reported-by: syzbot+ebc0b8ae5d3590b2c074@syzkaller.appspotmail.com Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/537 Fixes: c2b2ae3925b6 ("mptcp: handle correctly disconnect() failures") Tested-by: syzbot+ebc0b8ae5d3590b2c074@syzkaller.appspotmail.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> --- net/mptcp/protocol.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)