kernel BUG in submit_bh_wbc

Status: upstream: reported C repro on 2023/06/15 00:20
Bug presence: origin:lts
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+807c663f72dcf074e3e2@syzkaller.appspotmail.com
First crash: 1163d, last: 4h51m
Cause bisection: introduced by (bisect log) :
commit 8d5459c11f548131ce48b2fbf45cccc5c382558f
Author: Jan Kara <jack@suse.cz>
Date: Fri May 20 11:14:02 2022 +0000

  ext4: improve write performance with disabled delalloc

Crash: kernel BUG in submit_bh_wbc (log)
Repro: C syz .config
  
Fix bisection: fixed by (bisect log) :
commit 32b9fb9a67ec70bbe3afe931b0ea44203150a49a
Author: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Date: Mon Sep 18 10:45:50 2023 +0000

  ext4: mark buffer new if it is unwritten to avoid stale data exposure

  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2024/03/17 lts (merge base) 883d1a956208 C [report] kernel BUG in submit_bh_wbc
2024/03/31 upstream (ToT) 18737353cca0 C Didn't crash
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 kernel BUG in submit_bh_wbc origin:lts-only -1 syz, C done 19 806d 1234d 3/3 fixed on 2024/07/20 06:27
linux-6.6 kernel BUG in submit_bh_wbc -1 1 10d 10d 0/2 upstream: reported on 2026/08/11 15:13
upstream kernel BUG at fs/buffer.c:LINE! nilfs -1 syz, C done error 567 864d 3046d 25/29 fixed on 2024/04/10 03:59
upstream kernel BUG in submit_bh_wbc (2) udf -1 syz, C done 123 743d 848d 27/29 fixed on 2024/08/14 03:44
linux-4.14 kernel BUG at fs/buffer.c:LINE! -1 syz, C error 59 1278d 2672d 0/1 upstream: reported C repro on 2019/04/27 19:47
linux-6.1 kernel BUG in submit_bh_wbc (2) origin:lts-only -1 syz, C inconclusive 280 11d 756d 0/3 upstream: reported C repro on 2024/07/26 16:49
linux-4.19 kernel BUG at fs/buffer.c:LINE! (2) udf ext4 -1 syz, C error 31 1285d 2099d 0/1 upstream: reported C repro on 2020/11/21 07:48
android-54 kernel BUG at fs/buffer.c:LINE! ext4 -1 syz, C 4762 453d 2404d 0/2 upstream: reported C repro on 2020/01/21 13:12
upstream kernel BUG in submit_bh_wbc (3) nilfs fs -1 syz, C done 18 669d 676d 28/29 fixed on 2024/11/12 23:31
linux-5.15 kernel BUG in submit_bh_wbc -1 syz, C error 8 896d 1174d 0/3 auto-obsoleted due to no activity on 2024/06/16 14:58
upstream kernel BUG in submit_bh_wbc nilfs -1 syz, C done 10 849d 858d 25/29 fixed on 2024/04/24 18:26
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/03/11 21:14 3h12m bisect fix android14-6.1 OK (1) job log
2023/07/28 15:24 1h02m bisect fix android14-6.1 OK (0) job log log

Sample crash report:
------------[ cut here ]------------
kernel BUG at fs/buffer.c:2714!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 419 Comm: kmmpd-loop0 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:submit_bh_wbc+0x4c9/0x4f0 fs/buffer.c:2714
Code: c3 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c bd fe ff ff 48 89 df e8 68 d5 e7 ff e9 b0 fe ff ff e8 1e 38 a2 ff 0f 0b e8 17 38 a2 ff <0f> 0b e8 10 38 a2 ff 0f 0b e8 09 38 a2 ff 0f 0b e8 02 38 a2 ff 0f
RSP: 0018:ffffc90000b87ca0 EFLAGS: 00010293
RAX: ffffffff81cf3f59 RBX: 0000000000000000 RCX: ffff888118575100
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000b87cf0 R08: ffff888123ffdc7f R09: 1ffff110247ffb8f
R10: dffffc0000000000 R11: ffffed10247ffb90 R12: 0000000000000000
R13: 1ffff110247ffb8f R14: ffff888123ffdc78 R15: 0000000000003801
FS:  0000000000000000(0000) GS:ffff8881f6e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc8d0585fc0 CR3: 000000010fb65000 CR4: 00000000003506b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 submit_bh+0x1f/0x30 fs/buffer.c:2755
 write_mmp_block_thawed+0x397/0x510 fs/ext4/mmp.c:51
 write_mmp_block+0x138/0x2b0 fs/ext4/mmp.c:67
 kmmpd+0x215/0x950 fs/ext4/mmp.c:246
 kthread+0x281/0x320 kernel/kthread.c:386
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:submit_bh_wbc+0x4c9/0x4f0 fs/buffer.c:2714
Code: c3 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c bd fe ff ff 48 89 df e8 68 d5 e7 ff e9 b0 fe ff ff e8 1e 38 a2 ff 0f 0b e8 17 38 a2 ff <0f> 0b e8 10 38 a2 ff 0f 0b e8 09 38 a2 ff 0f 0b e8 02 38 a2 ff 0f
RSP: 0018:ffffc90000b87ca0 EFLAGS: 00010293
RAX: ffffffff81cf3f59 RBX: 0000000000000000 RCX: ffff888118575100
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000b87cf0 R08: ffff888123ffdc7f R09: 1ffff110247ffb8f
R10: dffffc0000000000 R11: ffffed10247ffb90 R12: 0000000000000000
R13: 1ffff110247ffb8f R14: ffff888123ffdc78 R15: 0000000000003801
FS:  0000000000000000(0000) GS:ffff8881f6f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fffc219fff8 CR3: 0000000134683000 CR4: 00000000003506a0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (2593):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/05/15 07:15 android14-6.1 cccf9748e7b1 6ccb967e .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-6-1 kernel BUG in submit_bh_wbc
2025/09/03 13:39 android14-6.1 79ccb6ecf51e 96a211bc .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-android-6-1 kernel BUG in submit_bh_wbc
2025/07/12 10:38 android14-6.1 e2deb0b42a3a 3cda49cf .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-android-6-1 kernel BUG in submit_bh_wbc
2025/06/15 19:48 android14-6.1 6246d345f550 5f4b362d .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-android-6-1 kernel BUG in submit_bh_wbc
2025/06/08 14:58 android14-6.1 7af56ffc913d 4826c28e .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-android-6-1 kernel BUG in submit_bh_wbc
2025/05/25 16:07 android14-6.1 3c6d0251e1fb ed351ea7 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci2-android-6-1 kernel BUG in submit_bh_wbc
2025/01/26 16:54 android14-6.1 ef4fb40b87a9 9fbd772e .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/12/16 06:57 android14-6.1 22b7ded8b55b 7cbfbb3a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/11/30 07:55 android14-6.1 a887a44ace2a 68914665 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/11/21 19:03 android14-6.1 51bee181735e 4b25d554 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/10/08 00:13 android14-6.1 0e8b65e41ffd d7906eff .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/09/25 06:24 android14-6.1 5c7d0d4f4a38 5643e0e9 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/08/20 20:36 android14-6.1 edca080b95df 9f0ab3fb .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2024/03/17 12:15 android14-6.1 ef39f76e4d24 d615901c .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2023/10/24 12:09 android14-6.1 8a67c0609445 af8d2e46 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2023/09/24 09:56 android14-6.1 060ebb378d1c 0b6a67ac .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2023/06/15 00:46 android14-6.1 60662882b7bd 76decb82 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2023/06/15 00:18 android14-6.1 60662882b7bd 76decb82 .config strace log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/21 12:48 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/21 11:09 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/20 21:05 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/20 04:11 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/19 19:24 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/19 15:21 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/18 23:15 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/18 14:42 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/18 05:05 android14-6.1 92668decd5e0 1e72964b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/17 17:02 android14-6.1 92668decd5e0 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/17 16:56 android14-6.1 92668decd5e0 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/17 14:13 android14-6.1 92668decd5e0 905244d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/16 11:02 android14-6.1 92668decd5e0 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/15 21:49 android14-6.1 92668decd5e0 746171ee .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/10 13:12 android14-6.1 92668decd5e0 5d63f80b .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/08 03:44 android14-6.1 92668decd5e0 e4ef95d6 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/05 13:47 android14-6.1 92668decd5e0 52aa2820 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/03 04:41 android14-6.1 92668decd5e0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/02 19:37 android14-6.1 92668decd5e0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/02 16:57 android14-6.1 92668decd5e0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/01 20:27 android14-6.1 92668decd5e0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/08/01 06:56 android14-6.1 92668decd5e0 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/31 12:56 android14-6.1 92668decd5e0 7664cf44 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/31 02:24 android14-6.1 92668decd5e0 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/30 18:25 android14-6.1 92668decd5e0 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/25 22:22 android14-6.1 92668decd5e0 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/25 12:44 android14-6.1 92668decd5e0 492bab15 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/22 12:50 android14-6.1 92668decd5e0 4a865b71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/22 12:50 android14-6.1 92668decd5e0 4a865b71 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/22 10:19 android14-6.1 72b456bf57ad b561ce9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/21 10:03 android14-6.1 72b456bf57ad 7c5de9c3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/20 10:45 android14-6.1 c7e15f0bdc49 de6a700d .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/20 02:41 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/19 06:30 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/18 21:43 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/18 04:46 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/18 03:44 android14-6.1 c7e15f0bdc49 72524a66 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/17 19:40 android14-6.1 c7e15f0bdc49 8aaff637 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/17 17:48 android14-6.1 c7e15f0bdc49 8aaff637 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/17 09:02 android14-6.1 c7e15f0bdc49 7f27c57a .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/16 09:16 android14-6.1 8824f345abdb 27a8bd60 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/14 18:25 android14-6.1 e69716042404 2130f682 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/13 23:16 android14-6.1 47455f9704a1 cc4833d0 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2026/07/12 14:00 android14-6.1 21b931853e8d d78ea535 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
2023/06/15 00:02 android14-6.1 60662882b7bd 76decb82 .config console log report info [disk image] [vmlinux] [kernel image] ci2-android-6-1 kernel BUG in submit_bh_wbc
* Struck through repros no longer work on HEAD.