WARNING in gfs2_check_blk_type

Status: upstream: reported C repro on 2026/10/18 22:36
Reported-by: syzbot+8a16b6d10bd3c920fd45@syzkaller.appspotmail.com
First crash: 6d23h, last: 6d07h
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 WARNING in gfs2_check_blk_type origin:upstream -1 syz, C error 72 49d 1224d 0/3 upstream: reported C repro on 2023/06/19 08:48
upstream WARNING in gfs2_check_blk_type (2) prio:low gfs2 -1 syz, C inconclusive 26 7d17h 964d 0/29 upstream: reported C repro on 2024/03/05 11:03
linux-6.1 WARNING in gfs2_check_blk_type origin:upstream -1 syz, C error 14 7d12h 1224d 0/3 upstream: reported C repro on 2023/06/19 08:08
upstream WARNING in gfs2_check_blk_type gfs2 -1 syz, C error done 67 1010d 1413d 25/29 fixed on 2024/03/04 12:43

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5930 at fs/gfs2/rgrp.c:2630 gfs2_rbm_from_block fs/gfs2/rgrp.c:279 [inline]
WARNING: CPU: 1 PID: 5930 at fs/gfs2/rgrp.c:2630 gfs2_check_blk_type+0x454/0x680 fs/gfs2/rgrp.c:2629
Modules linked in:
CPU: 1 PID: 5930 Comm: syz-executor Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:gfs2_check_blk_type+0x454/0x680 fs/gfs2/rgrp.c:2630
Code: 85 de 01 00 00 8b 1b 89 df 44 89 f6 e8 d5 f0 cd fd 4d 89 f5 44 39 f3 76 2c e8 48 ef cd fd 31 db e9 82 00 00 00 e8 3c ef cd fd <0f> 0b bb f9 ff ff ff 49 bd 00 00 00 00 00 fc ff df 4c 8b 64 24 08
RSP: 0018:ffffc900033ef880 EFLAGS: 00010293
RAX: ffffffff83b9a0c1 RBX: 0000000000000924 RCX: ffff888029928000
RDX: 0000000000000000 RSI: 0000000000000924 RDI: 000000020000001c
RBP: ffffc900033ef970 R08: ffff88805e897207 R09: 1ffff1100bd12e40
R10: dffffc0000000000 R11: ffffed100bd12e41 R12: ffff8880230da198
R13: 000000020000001c R14: ffffc900033ef8c0 R15: 1ffff1100461b439
FS:  0000555561463500(0000) GS:ffff8880b8d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffe2ce0dd00 CR3: 000000005ec73000 CR4: 00000000003506e0
Call Trace:
 <TASK>
 evict_should_delete fs/gfs2/super.c:1373 [inline]
 gfs2_evict_inode+0x816/0x13c0 fs/gfs2/super.c:1520
 evict+0x4b7/0x8a0 fs/inode.c:705
 __dentry_kill+0x412/0x630 fs/dcache.c:611
 dentry_kill+0xb8/0x290 fs/dcache.c:-1
 dput+0xfe/0x1e0 fs/dcache.c:918
 shrink_dcache_for_umount+0x69/0x110 fs/dcache.c:1703
 generic_shutdown_super+0x67/0x2b0 fs/super.c:665
 kill_block_super+0x44/0x90 fs/super.c:1668
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x3d7/0x460 fs/namespace.c:1259
 task_work_run+0x1d4/0x260 kernel/task_work.c:245
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:180
 exit_to_user_mode_prepare+0xee/0x180 kernel/entry/common.c:213
 __syscall_exit_to_user_mode_work kernel/entry/common.c:294 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:305
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd6f459f797
Code: a2 c7 05 5c 7f 25 00 00 00 00 00 eb 96 e8 e1 12 00 00 90 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 c7 c2 e8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffe2ce0e358 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fd6f4634efb RCX: 00007fd6f459f797
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffe2ce0e410
RBP: 00007ffe2ce0e410 R08: 00007ffe2ce0f410 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffe2ce0f4a0
R13: 00007fd6f4634efb R14: 000000000001a274 R15: 00007ffe2ce0f4e0
 </TASK>

Crashes (12):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/19 00:11 linux-6.6.y cecd39af8a1a 432c0077 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/19 14:52 linux-6.6.y cecd39af8a1a 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/19 14:52 linux-6.6.y cecd39af8a1a 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/19 14:52 linux-6.6.y cecd39af8a1a 72cdc28d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 23:02 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:53 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:50 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:47 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:44 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:41 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:38 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
2026/10/18 22:36 linux-6.6.y cecd39af8a1a 432c0077 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in gfs2_check_blk_type
* Struck through repros no longer work on HEAD.