syzbot


WARNING in tcp_recvmsg_locked (2)

Status: upstream: reported C repro on 2023/12/05 17:53
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+06dbd397158ec0ea4983@syzkaller.appspotmail.com
First crash: 707d, last: 3d14h
Cause bisection: introduced by (bisect log) :
commit 965b57b469a589d64d81b1688b38dcb537011bb0
Author: Cong Wang <cong.wang@bytedance.com>
Date: Wed Jun 15 16:20:12 2022 +0000

  net: Introduce a new proto_ops ->read_skb()

Crash: WARNING in tcp_recvmsg_locked (log)
Repro: C syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] WARNING in tcp_recvmsg_locked (2) 1 (2) 2023/12/05 18:38
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in tcp_recvmsg_locked net -1 1 847d 847d 0/29 auto-obsoleted due to no activity on 2023/11/06 08:49
linux-6.1 WARNING in tcp_recvmsg_locked origin:upstream -1 C error 1 519d 585d 0/3 upstream: reported C repro on 2024/04/04 07:11
Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/11/07 10:11 18m retest repro upstream report log
2025/10/17 17:55 13m retest repro upstream report log
2025/10/03 17:36 14m retest repro upstream report log
2025/09/19 17:19 13m retest repro upstream report log
2025/09/05 16:54 16m retest repro net report log
2025/08/22 07:00 24m retest repro net-next report log
2025/08/22 07:00 2h22m retest repro net-next report log
2025/08/08 01:53 23m retest repro upstream report log
2025/08/08 00:18 21m retest repro upstream error
2025/07/24 23:51 11m retest repro upstream report log
Fix bisection attempts (3)
Created Duration User Patch Repo Result
2024/08/21 02:40 2h53m bisect fix net-next OK (0) job log log
2024/02/24 06:46 2h56m bisect fix net-next OK (0) job log log
2024/01/18 14:44 6h50m bisect fix net-next OK (0) job log log

Sample crash report:
------------[ cut here ]------------
TCP recvmsg seq # bug 2: copied E92C873, seq E68D125, rcvnxt E7CEB7C, fl 40
WARNING: CPU: 1 PID: 5997 at net/ipv4/tcp.c:2724 tcp_recvmsg_locked+0xb2f/0x2910 net/ipv4/tcp.c:2724
Modules linked in:
CPU: 1 UID: 0 PID: 5997 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:tcp_recvmsg_locked+0xb2f/0x2910 net/ipv4/tcp.c:2724
Code: 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 b8 1c 00 00 48 8b 04 24 44 8b 44 24 30 89 da 48 c7 c7 40 73 cb 8c 8b 30 e8 42 79 b4 f7 90 <0f> 0b 90 90 e9 ad f9 ff ff e8 33 46 f6 f7 49 8d 5c 24 60 be 08 00
RSP: 0018:ffffc90003287478 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 000000000e68d125 RCX: ffffffff817b3ee8
RDX: ffff8880738c2480 RSI: ffffffff817b3ef5 RDI: 0000000000000001
RBP: ffff888071bf6df4 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: ffff888071bf6de8
R13: ffff888071bf6dc0 R14: 000000000000ffcb R15: dffffc0000000000
FS:  000055557cf69500(0000) GS:ffff888124b0a000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000f84000 CR3: 00000000774fc000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 receive_fallback_to_copy net/ipv4/tcp.c:1968 [inline]
 tcp_zerocopy_receive+0x131a/0x2120 net/ipv4/tcp.c:2200
 do_tcp_getsockopt+0xe28/0x26c0 net/ipv4/tcp.c:4713
 tcp_getsockopt+0xdf/0x100 net/ipv4/tcp.c:4812
 do_sock_getsockopt+0x34d/0x440 net/socket.c:2421
 __sys_getsockopt+0x12f/0x260 net/socket.c:2450
 __do_sys_getsockopt net/socket.c:2457 [inline]
 __se_sys_getsockopt net/socket.c:2454 [inline]
 __x64_sys_getsockopt+0xbd/0x160 net/socket.c:2454
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2e5758efc9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff6778beb8 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00007f2e577e5fa0 RCX: 00007f2e5758efc9
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000005
RBP: 00007f2e57611f91 R08: 0000200000000380 R09: 0000000000000000
R10: 0000200000000340 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f2e577e5fa0 R14: 00007f2e577e5fa0 R15: 0000000000000005
 </TASK>

Crashes (13):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/10/24 06:47 upstream 6fab32bb6508 c0460fcd .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in tcp_recvmsg_locked
2024/11/22 15:42 upstream 28eb75e178d3 4b25d554 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING in tcp_recvmsg_locked
2025/02/19 15:52 upstream 6537cfb395f3 cbd8edab .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in tcp_recvmsg_locked
2024/09/30 21:59 upstream 9852d85ec9d4 179f4029 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in tcp_recvmsg_locked
2024/06/23 08:39 upstream 563a50672d8a c2e07261 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in tcp_recvmsg_locked
2024/10/20 21:40 net 3b05b9c36ddd cd6fc0a3 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in tcp_recvmsg_locked
2024/12/18 19:39 net-next c1bad69f8baf 1432fc84 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in tcp_recvmsg_locked
2023/12/04 12:46 net-next 8470e4368b0f f819d6f7 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in tcp_recvmsg_locked
2024/10/21 19:52 upstream 42f7652d3eb5 a93682b3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING in tcp_recvmsg_locked
2024/09/19 16:24 upstream a430d95c5efa 6f888b75 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING in tcp_recvmsg_locked
2024/06/23 03:29 upstream 563a50672d8a c2e07261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream WARNING in tcp_recvmsg_locked
2024/03/14 07:29 net d7d75124965a f919f202 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING in tcp_recvmsg_locked
2023/12/04 09:44 net-next 8470e4368b0f f819d6f7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-kasan-gce WARNING in tcp_recvmsg_locked
* Struck through repros no longer work on HEAD.