syzbot


WARNING in subflow_data_ready (4)

Status: upstream: reported C repro on 2025/08/20 12:41
Subsystems: mptcp
[Documentation on labels]
Reported-by: syzbot+0ff6b771b4f7a5bce83b@syzkaller.appspotmail.com
Fix commit: 71154bbe4942 mptcp: fallback earlier on simult connection
Patched on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci-upstream-rust-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-usb], missing on: [ci-qemu2-riscv64]
First crash: 156d, last: 18d
Discussions (3)
Title Replies (including bot) Last reply
[PATCH net 0/2] mptcp: fix warn on bad status 2 (2) 2025/12/12 12:54
[syzbot] [mptcp?] WARNING in subflow_data_ready (4) 0 (4) 2025/11/27 07:45
[syzbot] Monthly mptcp report (Oct 2025) 0 (1) 2025/10/09 16:31
Similar bugs (5)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in subflow_data_ready mptcp -1 42 736d 821d 25/29 fixed on 2024/01/20 21:18
upstream WARNING in subflow_data_ready (3) mptcp -1 1 237d 237d 0/29 closed as invalid on 2025/06/27 12:28
linux-6.1 WARNING in subflow_data_ready origin:lts-only -1 C unreliable 11 4d13h 743d 0/3 upstream: reported C repro on 2024/01/11 08:07
upstream WARNING in subflow_data_ready (2) mptcp -1 C done 9 712d 730d 0/29 auto-obsoleted due to no activity on 2024/05/21 09:30
linux-6.6 WARNING in subflow_data_ready origin:upstream -1 C done 13 41d 44d 2/2 fixed on 2026/01/16 22:01
Last patch testing requests (2)
Created Duration User Patch Repo Result
2025/11/27 07:45 15m pabeni@redhat.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 8e621c9a3375 report log
2025/11/26 18:25 23m pabeni@redhat.com patch git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git main OK log

Sample crash report:
------------[ cut here ]------------
WARNING: net/mptcp/subflow.c:1528 at subflow_data_ready+0x49b/0x7c0 net/mptcp/subflow.c:1527, CPU#1: kworker/u8:10/3067
Modules linked in:
CPU: 1 UID: 0 PID: 3067 Comm: kworker/u8:10 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: krdsd rds_tcp_accept_worker
RIP: 0010:subflow_data_ready+0x49b/0x7c0 net/mptcp/subflow.c:1527
Code: 48 0f b9 3a e9 c9 fc ff ff e8 71 33 7b f6 48 89 df 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d e9 6b 0e 00 00 e8 56 33 7b f6 90 <0f> 0b 90 e9 f2 fd ff ff 90 0f 0b 90 43 0f b6 04 2f 84 c0 0f 85 a1
RSP: 0018:ffffc90000a08240 EFLAGS: 00010246
RAX: ffffffff8b45c22a RBX: ffff88802b45cf80 RCX: ffff88802fd13d00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffff8880334195cf R09: 1ffff110066832b9
R10: dffffc0000000000 R11: ffffed10066832ba R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888033418c80 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055558bae8808 CR3: 000000007b568000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 tcp_data_queue+0x1e14/0x5e30 net/ipv4/tcp_input.c:5461
 tcp_rcv_state_process+0x23a4/0x4520 net/ipv4/tcp_input.c:7185
 tcp_v6_do_rcv+0xbef/0x1ba0 net/ipv6/tcp_ipv6.c:1630
 tcp_v6_rcv+0x2247/0x2ae0 net/ipv6/tcp_ipv6.c:1877
 ip6_protocol_deliver_rcu+0xcb0/0x15c0 net/ipv6/ip6_input.c:438
 ip6_input_finish+0x191/0x370 net/ipv6/ip6_input.c:489
 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
 ip6_input+0x16a/0x270 net/ipv6/ip6_input.c:500
 NF_HOOK+0x30c/0x3a0 include/linux/netfilter.h:318
 __netif_receive_skb_one_core net/core/dev.c:6137 [inline]
 __netif_receive_skb+0xd3/0x380 net/core/dev.c:6250
 process_backlog+0x54f/0x1340 net/core/dev.c:6602
 __napi_poll+0xae/0x320 net/core/dev.c:7666
 napi_poll net/core/dev.c:7729 [inline]
 net_rx_action+0x64a/0xe00 net/core/dev.c:7881
 handle_softirqs+0x22b/0x7c0 kernel/softirq.c:622
 do_softirq+0x76/0xd0 kernel/softirq.c:523
 </IRQ>
 <TASK>
 __local_bh_enable_ip+0xf8/0x130 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:936 [inline]
 __dev_queue_xmit+0x1955/0x3140 net/core/dev.c:4844
 NF_HOOK_COND include/linux/netfilter.h:307 [inline]
 ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
 NF_HOOK include/linux/netfilter.h:318 [inline]
 ip6_xmit+0x11b5/0x1970 net/ipv6/ip6_output.c:371
 inet6_csk_xmit+0x4db/0x780 net/ipv6/inet6_connection_sock.c:120
 __tcp_transmit_skb+0x2092/0x3aa0 net/ipv4/tcp_output.c:1631
 tcp_transmit_skb net/ipv4/tcp_output.c:1649 [inline]
 tcp_write_xmit+0x16e8/0x6980 net/ipv4/tcp_output.c:3002
 __tcp_push_pending_frames+0x97/0x380 net/ipv4/tcp_output.c:3185
 __tcp_close+0x617/0xfe0 net/ipv4/tcp.c:3208
 tcp_close+0x28/0x110 net/ipv4/tcp.c:3299
 inet_release+0x144/0x190 net/ipv4/af_inet.c:437
 __sock_release net/socket.c:662 [inline]
 sock_release+0x85/0x150 net/socket.c:690
 rds_tcp_accept_one+0x71a/0x930 net/rds/tcp_listen.c:214
 rds_tcp_accept_worker+0x3e/0xa0 net/rds/tcp.c:529
 process_one_work kernel/workqueue.c:3257 [inline]
 process_scheduled_works+0xad1/0x1770 kernel/workqueue.c:3340
 worker_thread+0x8a0/0xda0 kernel/workqueue.c:3421
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
 </TASK>

Crashes (556):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/23 18:36 upstream b927546677c8 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in subflow_data_ready
2025/12/09 03:25 upstream c2f2b01b74be d1b870e1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/02 08:06 upstream 1d18101a644e d1b870e1 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/11/20 20:57 upstream 8e621c9a3375 2cc4c24a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/12 08:43 linux-next d9771d0dbe18 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/12 05:24 linux-next d9771d0dbe18 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/11 18:57 linux-next 5ce74bc1b7cb d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/11 14:49 linux-next 5ce74bc1b7cb d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/11 08:58 linux-next 5ce74bc1b7cb d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/11 01:37 linux-next 008d3547aae5 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/10 23:25 linux-next 008d3547aae5 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/30 14:11 upstream 8640b74557fc d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/30 07:12 upstream 8640b74557fc d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/30 04:21 upstream 8640b74557fc d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/28 23:26 upstream c875a6c32467 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in subflow_data_ready
2025/12/28 18:24 upstream d26143bb38e2 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/28 12:39 upstream d26143bb38e2 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/28 09:15 upstream d26143bb38e2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in subflow_data_ready
2025/12/27 09:33 upstream 3f0e9c8cefa9 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/27 08:10 upstream 3f0e9c8cefa9 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/26 21:04 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in subflow_data_ready
2025/12/26 17:35 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/26 02:09 upstream ccd1cdca5cd4 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce WARNING in subflow_data_ready
2025/12/26 00:40 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/25 18:30 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/25 16:27 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/25 15:36 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/25 12:55 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/25 10:12 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image] [vmlinux] [kernel image] ci-qemu-gce-upstream-auto WARNING in subflow_data_ready
2025/12/24 15:34 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in subflow_data_ready
2025/12/24 14:24 upstream b927546677c8 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-386 WARNING in subflow_data_ready
2025/12/29 13:38 upstream 7839932417dd d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/12/29 06:18 upstream c875a6c32467 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/12/29 00:46 upstream c875a6c32467 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/12/28 11:35 upstream d26143bb38e2 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/28 04:28 upstream d26143bb38e2 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/12/28 03:28 upstream d26143bb38e2 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/28 01:47 upstream d26143bb38e2 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/27 21:33 upstream c53f467229a7 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/27 13:08 upstream c53f467229a7 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/12/26 13:02 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/26 08:01 upstream ccd1cdca5cd4 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/26 05:56 upstream ccd1cdca5cd4 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/12/25 21:07 upstream ccd1cdca5cd4 d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root WARNING in subflow_data_ready
2025/08/20 11:14 upstream b19a97d57c15 79512909 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in subflow_data_ready
2025/12/27 20:17 upstream c53f467229a7 d1b870e1 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 WARNING in subflow_data_ready
2025/12/21 05:28 upstream d8ba32c5a460 e14dbeb9 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64-mte WARNING in subflow_data_ready
2025/11/25 08:59 upstream ac3fd01e4c1e 64219f15 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu2-arm64 WARNING in subflow_data_ready
2025/12/23 07:40 net dabac51b8102 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in subflow_data_ready
2025/12/24 23:30 net-next 7b8e9264f55a d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in subflow_data_ready
2026/01/05 00:04 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2026/01/04 22:42 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2026/01/02 23:04 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2026/01/02 14:51 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2026/01/02 06:20 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2026/01/02 02:12 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2026/01/01 15:24 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2026/01/01 06:44 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2026/01/01 04:02 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/31 13:37 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/31 09:57 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/30 10:40 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/30 03:19 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/29 20:05 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/28 17:38 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/28 06:00 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/27 11:02 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/27 04:03 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/26 19:37 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/26 14:09 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce WARNING in subflow_data_ready
2025/12/25 06:09 linux-next cc3aa43b44bd d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING in subflow_data_ready
2025/12/17 02:56 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 WARNING in subflow_data_ready
* Struck through repros no longer work on HEAD.