syzbot


WARNING: ODEBUG bug in generic_shutdown_super

Status: moderation: reported on 2026/03/11 01:51
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+919204cf63da1ba44446@syzkaller.appspotmail.com
First crash: 11d, last: 8d07h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 WARNING: ODEBUG bug in generic_shutdown_super (2) -1 80 14d 681d 0/3 upstream: reported on 2024/05/06 02:03
linux-6.1 WARNING: ODEBUG bug in generic_shutdown_super -1 2 812d 890d 0/3 auto-obsoleted due to no activity on 2024/04/05 01:21

Sample crash report:
------------[ 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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/03/10 12:10 upstream 1f318b96cc84 6972f302 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING: ODEBUG bug in generic_shutdown_super
2026/03/07 01:44 upstream 651690480a96 5cb44a80 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root WARNING: ODEBUG bug in generic_shutdown_super
* Struck through repros no longer work on HEAD.