[moderation] [fs?] WARNING: ODEBUG bug in generic_shutdown_super

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 1f318b96cc84 Linux 7.0-rc3
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1027375a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=779072223d02a312
dashboard link: https://syzkaller.appspot.com/bug?extid=919204cf63da1ba44446
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
CC: [bra...@kernel.org ja...@suse.cz linux-...@vger.kernel.org linux-...@vger.kernel.org vi...@zeniv.linux.org.uk]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/8145acc64f5b/disk-1f318b96.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/f0e2338fd00a/vmlinux-1f318b96.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d6b85b09ff32/bzImage-1f318b96.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+919204...@syzkaller.appspotmail.com

------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff88801cbd85a0 object type: work_struct hint: gfs2_withdraw_func+0x0/0x430 fs/gfs2/util.c:-1
WARNING: lib/debugobjects.c:632 at debug_print_object lib/debugobjects.c:629 [inline], CPU#0: syz-executor/5820
WARNING: lib/debugobjects.c:632 at __debug_check_no_obj_freed lib/debugobjects.c:1116 [inline], CPU#0: syz-executor/5820
WARNING: lib/debugobjects.c:632 at debug_check_no_obj_freed+0x405/0x550 lib/debugobjects.c:1146, CPU#0: syz-executor/5820
Modules linked in:
CPU: 0 UID: 0 PID: 5820 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:debug_print_object lib/debugobjects.c:629 [inline]
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:1116 [inline]
RIP: 0010:debug_check_no_obj_freed+0x44a/0x550 lib/debugobjects.c:1146
Code: 89 44 24 20 e8 d7 2e 77 fd 48 8b 44 24 20 4c 8b 4d 00 4c 89 ef 48 c7 c6 c0 b9 27 8c 48 c7 c2 40 bf 27 8c 8b 0c 24 4d 89 f8 50 <67> 48 0f b9 3a 48 83 c4 08 4c 8b 6c 24 18 48 b9 00 00 00 00 00 fc
RSP: 0018:ffffc9000375fc08 EFLAGS: 00010246
RAX: ffffffff84248ba0 RBX: ffffffff9a52b668 RCX: 0000000000000000
RDX: ffffffff8c27bf40 RSI: ffffffff8c27b9c0 RDI: ffffffff901c4ce0
RBP: ffffffff8bcb5f00 R08: ffff88801cbd85a0 R09: ffffffff8bcb7080
R10: dffffc0000000000 R11: ffffffff818e7ca0 R12: ffff88801cbda000
R13: ffffffff901c4ce0 R14: ffff88801cbd8000 R15: ffff88801cbd85a0
FS: 00005555768b5500(0000) GS:ffff888125463000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000400000 CR3: 000000004ef7c000 CR4: 0000000000350ef0
Call Trace:
<TASK>
slab_free_hook mm/slub.c:2623 [inline]
slab_free mm/slub.c:6168 [inline]
kfree+0x13a/0x630 mm/slub.c:6486
generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
kill_block_super+0x44/0x90 fs/super.c:1725
deactivate_locked_super+0xbc/0x130 fs/super.c:476
cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
task_work_run+0x1d9/0x270 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:67 [inline]
exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
__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 include/linux/entry-common.h:325 [inline]
do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f48d479d9d7
Code: a2 c7 05 1c ed 24 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:00007ffc68a669d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: 0000000000000000 RBX: 00007f48d4831f90 RCX: 00007f48d479d9d7
RDX: 0000000000000000 RSI: 0000000000000009 RDI: 00007ffc68a66a90
RBP: 00007ffc68a66a90 R08: 00007ffc68a67a90 R09: 00000000ffffffff
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc68a67b20
R13: 00007f48d4831f90 R14: 000000000010ace6 R15: 00007ffc68a67b60
</TASK>
----------------
Code disassembly (best guess):
0: 89 44 24 20 mov %eax,0x20(%rsp)
4: e8 d7 2e 77 fd call 0xfd772ee0
9: 48 8b 44 24 20 mov 0x20(%rsp),%rax
e: 4c 8b 4d 00 mov 0x0(%rbp),%r9
12: 4c 89 ef mov %r13,%rdi
15: 48 c7 c6 c0 b9 27 8c mov $0xffffffff8c27b9c0,%rsi
1c: 48 c7 c2 40 bf 27 8c mov $0xffffffff8c27bf40,%rdx
23: 8b 0c 24 mov (%rsp),%ecx
26: 4d 89 f8 mov %r15,%r8
29: 50 push %rax
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 48 83 c4 08 add $0x8,%rsp
33: 4c 8b 6c 24 18 mov 0x18(%rsp),%r13
38: 48 rex.W
39: b9 00 00 00 00 mov $0x0,%ecx
3e: 00 fc add %bh,%ah


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