linux-kernel - [syzbot] [jfs?] general protection fault in inode_cgwb_move_to

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Message-ID: <693213f1.a70a0220.d98e3.01de.GAE@google.com>
Date: Thu, 04 Dec 2025 15:06:25 -0800
From: syzbot <syzbot+90f56ac0963995f6a919@...kaller.appspotmail.com>
To: jfs-discussion@...ts.sourceforge.net, linux-kernel@...r.kernel.org, 
	shaggy@...nel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [jfs?] general protection fault in inode_cgwb_move_to_attached

Hello,

syzbot found the following issue on:

HEAD commit:    7d31f578f323 Add linux-next specific files for 20251128
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=142970c2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6336d8e94a7c517d
dashboard link: https://syzkaller.appspot.com/bug?extid=90f56ac0963995f6a919
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: https://storage.googleapis.com/syzbot-assets/6b49d8ad90de/disk-7d31f578.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/dbe2d4988ca7/vmlinux-7d31f578.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0448ab2411/bzImage-7d31f578.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+90f56ac0963995f6a919@...kaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0104620b0f: 0000 [#1] SMP KASAN PTI
KASAN: probably user-memory-access in range [0x0000000823105878-0x000000082310587f]
CPU: 0 UID: 0 PID: 5833 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:__list_del_entry_valid_or_report+0xa6/0x190 lib/list_debug.c:65
Code: 4d 89 fc 49 c1 ec 03 43 80 3c 2c 00 74 08 4c 89 ff e8 fe 5c 90 fd 49 39 1f 0f 85 92 00 00 00 4d 8d 7e 08 4d 89 fc 49 c1 ec 03 <43> 80 3c 2c 00 74 08 4c 89 ff e8 db 5c 90 fd 49 39 1f 0f 85 9e 00
RSP: 0018:ffffc900041df8a8 EFLAGS: 00010206
RAX: 1ffff1100a98fb05 RBX: ffff888054c7d828 RCX: ffff88802b525b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff888054c7d830
RBP: 0000000000000001 R08: ffff888054c7d71b R09: 1ffff1100a98fae3
R10: dffffc0000000000 R11: ffffed100a98fae4 R12: 0000000104620b0f
R13: dffffc0000000000 R14: 0000000823105870 R15: 0000000823105878
FS:  0000555557b3f500(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc8a55156c0 CR3: 0000000064058000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __list_del_entry_valid include/linux/list.h:132 [inline]
 __list_del_entry include/linux/list.h:223 [inline]
 list_del_init include/linux/list.h:295 [inline]
 inode_cgwb_move_to_attached+0x294/0x580 fs/fs-writeback.c:323
 writeback_single_inode+0x655/0xc70 fs/fs-writeback.c:1875
 write_inode_now+0x160/0x1d0 fs/fs-writeback.c:2924
 iput_final fs/inode.c:1941 [inline]
 iput+0xa77/0x1030 fs/inode.c:2003
 jfs_umount+0x199/0x3c0 fs/jfs/jfs_umount.c:65
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x135/0x2c0 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1722
 deactivate_locked_super+0xbc/0x130 fs/super.c:474
 cleanup_mnt+0x425/0x4c0 fs/namespace.c:1328
 task_work_run+0x1d4/0x260 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:44 [inline]
 exit_to_user_mode_loop+0xff/0x4f0 kernel/entry/common.c:75
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline]
 do_syscall_64+0x2e3/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fad1a390a77
Code: a8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 0f 1f 44 00 00 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 a8 ff ff ff f7 d8 64 89 02 b8
RSP: 002b:00007ffffbd10c18 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007fad1a413d7d RCX: 00007fad1a390a77
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffffbd10cd0
RBP: 00007ffffbd10cd0 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007ffffbd11d60
R13: 00007fad1a413d7d R14: 000000000002fabf R15: 00007ffffbd11da0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:__list_del_entry_valid_or_report+0xa6/0x190 lib/list_debug.c:65
Code: 4d 89 fc 49 c1 ec 03 43 80 3c 2c 00 74 08 4c 89 ff e8 fe 5c 90 fd 49 39 1f 0f 85 92 00 00 00 4d 8d 7e 08 4d 89 fc 49 c1 ec 03 <43> 80 3c 2c 00 74 08 4c 89 ff e8 db 5c 90 fd 49 39 1f 0f 85 9e 00
RSP: 0018:ffffc900041df8a8 EFLAGS: 00010206
RAX: 1ffff1100a98fb05 RBX: ffff888054c7d828 RCX: ffff88802b525b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff888054c7d830
RBP: 0000000000000001 R08: ffff888054c7d71b R09: 1ffff1100a98fae3
R10: dffffc0000000000 R11: ffffed100a98fae4 R12: 0000000104620b0f
R13: dffffc0000000000 R14: 0000000823105870 R15: 0000000823105878
FS:  0000555557b3f500(0000) GS:ffff888125e4f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc8a55156c0 CR3: 0000000064058000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	4d 89 fc             	mov    %r15,%r12
   3:	49 c1 ec 03          	shr    $0x3,%r12
   7:	43 80 3c 2c 00       	cmpb   $0x0,(%r12,%r13,1)
   c:	74 08                	je     0x16
   e:	4c 89 ff             	mov    %r15,%rdi
  11:	e8 fe 5c 90 fd       	call   0xfd905d14
  16:	49 39 1f             	cmp    %rbx,(%r15)
  19:	0f 85 92 00 00 00    	jne    0xb1
  1f:	4d 8d 7e 08          	lea    0x8(%r14),%r15
  23:	4d 89 fc             	mov    %r15,%r12
  26:	49 c1 ec 03          	shr    $0x3,%r12
* 2a:	43 80 3c 2c 00       	cmpb   $0x0,(%r12,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	4c 89 ff             	mov    %r15,%rdi
  34:	e8 db 5c 90 fd       	call   0xfd905d14
  39:	49 39 1f             	cmp    %rbx,(%r15)
  3c:	0f                   	.byte 0xf
  3d:	85                   	.byte 0x85
  3e:	9e                   	sahf


---
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