syzbot


kernel BUG in ocfs2_block_group_search

Status: upstream: reported C repro on 2026/01/03 22:53
Subsystems: ocfs2
[Documentation on labels]
Reported-by: syzbot+44c564a3cb08605f34a1@syzkaller.appspotmail.com
First crash: 15d, last: 1d20h
Discussions (3)
Title Replies (including bot) Last reply
[PATCH v2] ocfs2: validate allocator type to prevent BUG_ON in ocfs2_block_group_search 1 (1) 2026/01/10 05:44
[PATCH] ocfs2: validate allocator type to prevent BUG_ON in ocfs2_block_group_search 3 (3) 2026/01/10 05:38
[syzbot] [ocfs2?] kernel BUG in ocfs2_block_group_search 0 (2) 2026/01/04 01:15
Last patch testing requests (4)
Created Duration User Patch Repo Result
2026/01/14 00:50 14m retest repro upstream report log
2026/01/14 00:50 14m retest repro upstream report log
2026/01/14 00:50 14m retest repro upstream report log
2026/01/04 01:15 20m kartikey406@gmail.com patch upstream OK log

Sample crash report:
=======================================================
JBD2: Ignoring recovery information on journal
ocfs2: Mounting device (7,0) on (node local, slot 0) with ordered data mode.
------------[ cut here ]------------
kernel BUG at fs/ocfs2/suballoc.c:1611!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5527 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:ocfs2_block_group_search+0x367/0x490 fs/ocfs2/suballoc.c:1611
Code: d9 80 e1 07 80 c1 03 38 c1 0f 8c c5 fe ff ff 48 89 df e8 0c 40 77 fe e9 b8 fe ff ff e8 92 95 0f fe 90 0f 0b e8 8a 95 0f fe 90 <0f> 0b f3 0f 1e fa 65 44 8b 3d 4f 2e cf 0e bf 07 00 00 00 44 89 fe
RSP: 0018:ffffc90002616bb8 EFLAGS: 00010293
RAX: ffffffff83b171d6 RBX: 000000000000004a RCX: ffff888000b70000
RDX: 0000000000000000 RSI: 000000000000004a RDI: 000000000000004a
RBP: 0000000000000001 R08: 00000000ffffffff R09: ffffc900026171a0
R10: dffffc0000000000 R11: ffffffff83b16e70 R12: ffff8880470b0740
R13: ffff88804453c740 R14: ffff8880230d7000 R15: 000000000000004a
FS:  000055556aa08500(0000) GS:ffff88808d416000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fbdcf97f000 CR3: 00000000113be000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 ocfs2_search_chain+0x5f3/0x1d60 fs/ocfs2/suballoc.c:1836
 ocfs2_claim_suballoc_bits+0xc1e/0x1f60 fs/ocfs2/suballoc.c:2011
 ocfs2_claim_new_inode+0x332/0x7a0 fs/ocfs2/suballoc.c:2303
 ocfs2_mknod_locked+0x100/0x250 fs/ocfs2/namei.c:638
 ocfs2_mknod+0x10a5/0x2030 fs/ocfs2/namei.c:385
 ocfs2_create+0x195/0x420 fs/ocfs2/namei.c:677
 lookup_open fs/namei.c:4440 [inline]
 open_last_lookups fs/namei.c:4540 [inline]
 path_openat+0x18bb/0x3dd0 fs/namei.c:4784
 do_filp_open+0x1fa/0x410 fs/namei.c:4814
 do_sys_openat2+0x121/0x200 fs/open.c:1430
 do_sys_open fs/open.c:1436 [inline]
 __do_sys_openat fs/open.c:1452 [inline]
 __se_sys_openat fs/open.c:1447 [inline]
 __x64_sys_openat+0x138/0x170 fs/open.c:1447
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe1e2d8f7c9
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:00007fff02afc7a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fe1e2fe5fa0 RCX: 00007fe1e2d8f7c9
RDX: 000000000000275a RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007fe1e2e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe1e2fe5fa0 R14: 00007fe1e2fe5fa0 R15: 0000000000000004
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:ocfs2_block_group_search+0x367/0x490 fs/ocfs2/suballoc.c:1611
Code: d9 80 e1 07 80 c1 03 38 c1 0f 8c c5 fe ff ff 48 89 df e8 0c 40 77 fe e9 b8 fe ff ff e8 92 95 0f fe 90 0f 0b e8 8a 95 0f fe 90 <0f> 0b f3 0f 1e fa 65 44 8b 3d 4f 2e cf 0e bf 07 00 00 00 44 89 fe
RSP: 0018:ffffc90002616bb8 EFLAGS: 00010293
RAX: ffffffff83b171d6 RBX: 000000000000004a RCX: ffff888000b70000
RDX: 0000000000000000 RSI: 000000000000004a RDI: 000000000000004a
RBP: 0000000000000001 R08: 00000000ffffffff R09: ffffc900026171a0
R10: dffffc0000000000 R11: ffffffff83b16e70 R12: ffff8880470b0740
R13: ffff88804453c740 R14: ffff8880230d7000 R15: 000000000000004a
FS:  000055556aa08500(0000) GS:ffff88808d416000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fd8f777e286 CR3: 00000000113be000 CR4: 0000000000352ef0

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/31 00:23 upstream dbf8fe85a16a d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-snapshot-upstream-root kernel BUG in ocfs2_block_group_search
2025/12/30 23:50 upstream dbf8fe85a16a d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-snapshot-upstream-root kernel BUG in ocfs2_block_group_search
2025/12/30 23:20 upstream dbf8fe85a16a d1b870e1 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro (clean fs)] ci-snapshot-upstream-root kernel BUG in ocfs2_block_group_search
2025/12/30 22:49 upstream dbf8fe85a16a d1b870e1 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root kernel BUG in ocfs2_block_group_search
* Struck through repros no longer work on HEAD.