[syzbot] [gfs2?] kernel BUG in gfs2_unpin

Hello,

syzbot found the following issue on:

HEAD commit:    b927546677c8 Merge tag 'dma-mapping-6.19-2025-12-22' of gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1681cd84580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=513255d80ab78f2b
dashboard link: https://syzkaller.appspot.com/bug?extid=0c5024a57ccf4017c187
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

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

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-b9275466.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/16f89c42bab9/vmlinux-b9275466.xz
kernel image: https://storage.googleapis.com/syzbot-assets/54c5ab9b0ef0/bzImage-b9275466.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email protected]

syz.0.0: attempt to access beyond end of device
loop0: rw=8390657, sector=68719479344, nr_sectors = 8 limit=32768
Buffer I/O error on dev loop0, logical block 8589934918, lost async page write
------------[ cut here ]------------
kernel BUG at fs/gfs2/lops.c:107!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5355 Comm: syz.0.0 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:gfs2_unpin+0x9ac/0x9c0 fs/gfs2/lops.c:107
Code: fe e9 24 fb ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 52 fb ff ff 4c 89 e7 e8 cf a6 25 fe e9 45 fb ff ff e8 25 fb bd fd 90 <0f> 0b e8 1d fb bd fd 90 0f 0b e8 15 fb bd fd 90 0f 0b 66 90 90 90
RSP: 0018:ffffc9000ae771b0 EFLAGS: 00010293
RAX: ffffffff840309fb RBX: ffff8880458af000 RCX: ffff88801f9e8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 1ffff11008b15e09 R08: ffff8880548e3917 R09: 1ffff1100a91c722
R10: dffffc0000000000 R11: ffffed100a91c723 R12: dffffc0000000000
R13: ffff8880458ae230 R14: ffff8880548e3910 R15: ffff888000e30000
FS:  00007fc9591536c0(0000) GS:ffff88808d416000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000010f15000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 databuf_lo_after_commit+0x15e/0x1b0 fs/gfs2/lops.c:1077
 lops_after_commit fs/gfs2/lops.h:51 [inline]
 gfs2_log_flush+0xf60/0x24c0 fs/gfs2/log.c:1110
 gfs2_jdata_writepages+0xf9/0x150 fs/gfs2/aops.c:370
 do_writepages+0x32e/0x550 mm/page-writeback.c:2598
 filemap_writeback mm/filemap.c:387 [inline]
 filemap_fdatawrite_range mm/filemap.c:412 [inline]
 filemap_write_and_wait_range+0x21f/0x320 mm/filemap.c:684
 filemap_write_and_wait include/linux/pagemap.h:65 [inline]
 iomap_bmap+0x1a6/0x3c0 fs/iomap/fiemap.c:106
 gfs2_bmap+0x171/0x200 fs/gfs2/aops.c:573
 bmap+0xac/0xe0 fs/inode.c:2040
 ioctl_fibmap fs/ioctl.c:76 [inline]
 file_ioctl+0x41d/0x780 fs/ioctl.c:326
 do_vfs_ioctl+0xb33/0x1430 fs/ioctl.c:576
 __do_sys_ioctl fs/ioctl.c:595 [inline]
 __se_sys_ioctl+0x82/0x170 fs/ioctl.c:583
 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: 0033:0x7fc95838f7c9
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:00007fc959153038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fc9585e6180 RCX: 00007fc95838f7c9
RDX: 0000200000000280 RSI: 0000000000000001 RDI: 0000000000000008
RBP: 00007fc958413f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc9585e6218 R14: 00007fc9585e6180 R15: 00007ffede3a3fa8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:gfs2_unpin+0x9ac/0x9c0 fs/gfs2/lops.c:107
Code: fe e9 24 fb ff ff 44 89 e1 80 e1 07 80 c1 03 38 c1 0f 8c 52 fb ff ff 4c 89 e7 e8 cf a6 25 fe e9 45 fb ff ff e8 25 fb bd fd 90 <0f> 0b e8 1d fb bd fd 90 0f 0b e8 15 fb bd fd 90 0f 0b 66 90 90 90
RSP: 0018:ffffc9000ae771b0 EFLAGS: 00010293
RAX: ffffffff840309fb RBX: ffff8880458af000 RCX: ffff88801f9e8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002
RBP: 1ffff11008b15e09 R08: ffff8880548e3917 R09: 1ffff1100a91c722
R10: dffffc0000000000 R11: ffffed100a91c723 R12: dffffc0000000000
R13: ffff8880458ae230 R14: ffff8880548e3910 R15: ffff888000e30000
FS:  00007fc9591536c0(0000) GS:ffff88808d416000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000010f15000 CR4: 0000000000352ef0


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