syzbot


WARNING in kcm_write_msgs

Status: upstream: reported C repro on 2024/04/23 04:47
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+b490d5e95bd8ecce1aeb@syzkaller.appspotmail.com
First crash: 427d, last: 1d14h
Bug presence (2)
Date Name Commit Repro Result
2024/04/24 linux-5.15.y (ToT) c52b9710c83d C [report] WARNING in kcm_write_msgs
2024/04/24 upstream (ToT) 9d1ddab261f3 C Didn't crash
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING in kcm_write_msgs origin:upstream C error 2 297d 574d 0/3 upstream: reported C repro on 2023/11/28 05:07
upstream WARNING in kcm_write_msgs net C done 620 9h48m 1923d 0/29 upstream: reported C repro on 2020/03/19 07:10
linux-4.14 WARNING in kcm_write_msgs C inconclusive 2 893d 1899d 0/1 upstream: reported C repro on 2020/04/12 04:13
linux-4.19 WARNING in kcm_write_msgs C error 8 888d 1912d 0/1 upstream: reported C repro on 2020/03/30 19:34
Last patch testing requests (4)
Created Duration User Patch Repo Result
2025/05/05 22:59 10m retest repro linux-5.15.y report log
2025/02/21 01:55 11m retest repro linux-5.15.y report log
2024/12/12 19:01 10m retest repro linux-5.15.y report log
2024/10/03 11:30 57m retest repro linux-5.15.y report log
Fix bisection attempts (4)
Created Duration User Patch Repo Result
2025/04/08 01:10 10m fix candidate upstream error job log
2024/09/26 02:07 4m fix candidate upstream error job log
2024/07/08 12:09 50m fix candidate upstream error job log
2024/04/24 15:54 26m fix candidate upstream error job log

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 4253 at net/kcm/kcmsock.c:633 kcm_write_msgs+0x102e/0x12e0 net/kcm/kcmsock.c:633
Modules linked in:
CPU: 0 PID: 4253 Comm: syz-executor243 Not tainted 5.15.185-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:kcm_write_msgs+0x102e/0x12e0 net/kcm/kcmsock.c:633
Code: ff 44 89 f6 e8 43 54 8b f8 45 85 f6 45 0f 45 fe 44 89 f8 48 81 c4 a0 00 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 c2 50 8b f8 <0f> 0b 41 bf ea ff ff ff 48 83 7c 24 48 00 0f 85 2f ff ff ff e9 50
RSP: 0018:ffffc900030ef8a8 EFLAGS: 00010293
RAX: ffffffff88ec715e RBX: 0000000000000000 RCX: ffff888029349dc0
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: dffffc0000000000 R08: dffffc0000000000 R09: fffffbfff1ff3636
R10: fffffbfff1ff3636 R11: 1ffffffff1ff3635 R12: 0000000000000000
R13: ffff8880220b6c80 R14: 0000000000000000 R15: 0000000000008000
FS:  00007f02a325a6c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdb57d0910 CR3: 000000002a93f000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kcm_sendmsg+0x1b3a/0x2130 net/kcm/kcmsock.c:1040
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x29c/0x380 net/socket.c:1079
 call_write_iter include/linux/fs.h:2172 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x712/0xd00 fs/read_write.c:594
 ksys_write+0x14d/0x250 fs/read_write.c:647
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7f02a329e1d9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 91 1a 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:00007f02a325a218 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f02a332a428 RCX: 00007f02a329e1d9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006
RBP: 00007f02a332a420 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f02a32f6394
R13: 0000200000002800 R14: 0000200000002950 R15: 0000200000002940
 </TASK>

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/06/23 07:37 linux-5.15.y 1c700860e8bc d6cdfb8a .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in kcm_write_msgs
2024/04/23 04:47 linux-5.15.y c52b9710c83d 36c961ad .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in kcm_write_msgs
* Struck through repros no longer work on HEAD.