[moderation] [gfs2?] general protection fault in __gfs2_trans_begin

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b4911fb0b060 Merge tag 'mmc-v6.16-rc1' of git://git.kernel..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13da3770580000
kernel config: https://syzkaller.appspot.com/x/.config?x=894c6f99e8e3313b
dashboard link: https://syzkaller.appspot.com/bug?extid=123ee6c4e79356bfc139
compiler: gcc (Debian 12.2.0-14+deb12u1) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
CC: [agru...@redhat.com gf...@lists.linux.dev linux-...@vger.kernel.org]

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3875a2c3b1be/disk-b4911fb0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/971ce3dd5072/vmlinux-b4911fb0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c18ae8de7fa6/bzImage-b4911fb0.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+123ee6...@syzkaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000011: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f]
CPU: 1 UID: 0 PID: 25 Comm: kworker/1:0H Not tainted 6.16.0-rc4-syzkaller-00049-gb4911fb0b060 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: gfs2-glock/syz:syz glock_work_func
RIP: 0010:__gfs2_trans_begin+0x3b1/0xb80 fs/gfs2/trans.c:73
Code: 80 3c 02 00 0f 85 8b 07 00 00 4c 8b a5 00 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 8c 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 57
RSP: 0018:ffffc900001f7960 EFLAGS: 00010217
RAX: dffffc0000000000 RBX: ffffc900001f7a40 RCX: ffffffff840b3fc7
RDX: 0000000000000011 RSI: ffffffff840b3fd5 RDI: 000000000000008c
RBP: ffff888025440000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 1ffff9200003ef2f R14: 0000000000000004 R15: ffff8880254400a8
FS: 0000000000000000(0000) GS:ffff888124859000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30710ff8 CR3: 00000000357fe000 CR4: 0000000000350ef0
Call Trace:
<TASK>
gfs2_ail_empty_gl+0x239/0x2f0 fs/gfs2/glops.c:129
inode_go_sync+0x21d/0x590 fs/gfs2/glops.c:335
do_xmote+0x3c1/0xf70 fs/gfs2/glock.c:731
run_queue+0x4c4/0x6d0 fs/gfs2/glock.c:871
glock_work_func+0x127/0x4d0 fs/gfs2/glock.c:1096
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d7/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__gfs2_trans_begin+0x3b1/0xb80 fs/gfs2/trans.c:73
Code: 80 3c 02 00 0f 85 8b 07 00 00 4c 8b a5 00 09 00 00 48 b8 00 00 00 00 00 fc ff df 49 8d bc 24 8c 00 00 00 48 89 fa 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 57
RSP: 0018:ffffc900001f7960 EFLAGS: 00010217
RAX: dffffc0000000000 RBX: ffffc900001f7a40 RCX: ffffffff840b3fc7
RDX: 0000000000000011 RSI: ffffffff840b3fd5 RDI: 000000000000008c
RBP: ffff888025440000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 1ffff9200003ef2f R14: 0000000000000004 R15: ffff8880254400a8
FS: 0000000000000000(0000) GS:ffff888124859000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30515ff8 CR3: 000000005eef4000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
0: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
4: 0f 85 8b 07 00 00 jne 0x795
a: 4c 8b a5 00 09 00 00 mov 0x900(%rbp),%r12
11: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
18: fc ff df
1b: 49 8d bc 24 8c 00 00 lea 0x8c(%r12),%rdi
22: 00
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx <-- trapping instruction
2e: 48 89 f8 mov %rdi,%rax
31: 83 e0 07 and $0x7,%eax
34: 83 c0 03 add $0x3,%eax
37: 38 d0 cmp %dl,%al
39: 7c 08 jl 0x43
3b: 84 d2 test %dl,%dl
3d: 0f .byte 0xf
3e: 85 .byte 0x85
3f: 57 push %rdi


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[syzbot]

Sending this report to the next reporting stage.