syzbot


WARNING: ODEBUG bug in __run_timers

Status: upstream: reported on 2025/09/06 01:04
Reported-by: syzbot+147eac264e42c8134929@syzkaller.appspotmail.com
First crash: 1d22h, last: 10h27m
Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: ODEBUG bug in __run_timers net -1 1 1813d 1809d 0/29 auto-closed as invalid on 2020/12/19 18:17
upstream WARNING: ODEBUG bug in __run_timers (3) hams -1 34 6h22m 5d06h 0/29 upstream: reported on 2025/09/02 17:24
upstream WARNING: ODEBUG bug in __run_timers (2) net -1 2 1503d 1528d 0/29 auto-closed as invalid on 2021/10/25 11:37
linux-6.1 WARNING: ODEBUG bug in __run_timers -1 1 1d16h 1d16h 0/3 upstream: reported on 2025/09/06 07:06

Sample crash report:
------------[ cut here ]------------
ODEBUG: free active (active state 0) object: ffff888020de4490 object type: timer_list hint: rose_t0timer_expiry+0x0/0x350
WARNING: CPU: 1 PID: 5156 at lib/debugobjects.c:518 debug_print_object lib/debugobjects.c:515 [inline]
WARNING: CPU: 1 PID: 5156 at lib/debugobjects.c:518 __debug_check_no_obj_freed lib/debugobjects.c:990 [inline]
WARNING: CPU: 1 PID: 5156 at lib/debugobjects.c:518 debug_check_no_obj_freed+0x446/0x540 lib/debugobjects.c:1020
Modules linked in:
CPU: 1 PID: 5156 Comm: udevd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:debug_print_object lib/debugobjects.c:515 [inline]
RIP: 0010:__debug_check_no_obj_freed lib/debugobjects.c:990 [inline]
RIP: 0010:debug_check_no_obj_freed+0x446/0x540 lib/debugobjects.c:1020
Code: 4c 8b 4d 00 48 c7 c7 80 7a fc 8a 48 c7 c6 e0 76 fc 8a 48 c7 c2 00 7c fc 8a 8b 0c 24 4d 89 f8 41 55 e8 be 2e 2a fd 48 83 c4 08 <0f> 0b 4c 8b 6c 24 18 48 b9 00 00 00 00 00 fc ff df ff 05 b3 e8 24
RSP: 0018:ffffc900001f0a50 EFLAGS: 00010296
RAX: e041870a7a4f7600 RBX: ffffffff97177750 RCX: ffff88807d89bc00
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffffff8aac9e00 R08: ffffc900001f0647 R09: 1ffff9200003e0c8
R10: dffffc0000000000 R11: fffff5200003e0c9 R12: ffff888020de4600
R13: ffffffff8966e8e0 R14: ffff888020de4000 R15: ffff888020de4490
FS:  00007f893321d880(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055556909c5c8 CR3: 00000000192d3000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 slab_free_hook mm/slub.c:1781 [inline]
 slab_free_freelist_hook+0xd2/0x1b0 mm/slub.c:1832
 slab_free mm/slub.c:3816 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3829
 rose_neigh_put include/net/rose.h:166 [inline]
 rose_timer_expiry+0x4c6/0x5f0 net/rose/rose_timer.c:183
 call_timer_fn+0x16e/0x530 kernel/time/timer.c:1700
 expire_timers kernel/time/timer.c:1751 [inline]
 __run_timers+0x52d/0x7d0 kernel/time/timer.c:2022
 run_timer_softirq+0x67/0xf0 kernel/time/timer.c:2035
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xc7/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:d_really_is_negative include/linux/dcache.h:466 [inline]
RIP: 0010:kernfs_dentry_node fs/kernfs/kernfs-internal.h:102 [inline]
RIP: 0010:kernfs_dop_revalidate+0x2f0/0x570 fs/kernfs/dir.c:1166
Code: bd 00 00 00 00 00 fc ff df 80 3c 28 00 74 08 4c 89 ef e8 b3 da ca ff 4d 8b 6d 00 49 83 c5 68 4c 89 e8 48 c1 e8 03 80 3c 28 00 <74> 08 4c 89 ef e8 96 da ca ff 4d 8b 6d 00 4d 85 ed 74 53 e8 38 94
RSP: 0018:ffffc900032477f0 EFLAGS: 00000246
RAX: 1ffff1100f30a556 RBX: ffff8880211897f0 RCX: 0000000000000000
RDX: ffff88807d89bc00 RSI: 0000000000000000 RDI: 00000000ffffffff
RBP: dffffc0000000000 R08: ffff8880211897c7 R09: 1ffff110042312f8
R10: dffffc0000000000 R11: ffffed10042312f9 R12: 1ffff110042312fe
R13: ffff888079852ab0 R14: ffff888021c5a8d0 R15: ffff8880211897c0
 d_revalidate fs/namei.c:862 [inline]
 lookup_fast+0x1f6/0x4d0 fs/namei.c:-1
 walk_component fs/namei.c:1998 [inline]
 link_path_walk+0x5ff/0xe00 fs/namei.c:2329
 path_openat+0x283/0x3190 fs/namei.c:3785
 do_filp_open+0x1c5/0x3d0 fs/namei.c:3816
 do_sys_openat2+0x12c/0x1c0 fs/open.c:1419
 do_sys_open fs/open.c:1434 [inline]
 __do_sys_openat fs/open.c:1450 [inline]
 __se_sys_openat fs/open.c:1445 [inline]
 __x64_sys_openat+0x139/0x160 fs/open.c:1445
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8933315c3a
Code: 41 89 f2 48 89 54 24 e0 41 83 e2 40 75 2a 89 f0 f7 d0 a9 00 00 41 00 74 1f 89 f2 b8 01 01 00 00 48 89 fe bf 9c ff ff ff 0f 05 <48> 3d 00 f0 ff ff 77 2e c3 0f 1f 44 00 00 48 8d 44 24 08 c7 44 24
RSP: 002b:00007ffce3fc66d8 EFLAGS: 00000206 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 000055ed5f6387a0 RCX: 00007f8933315c3a
RDX: 0000000000090800 RSI: 000055ed5f6298e0 RDI: 00000000ffffff9c
RBP: 000055ed5f6298e0 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000206 R12: 000055ed5f6227b0
R13: 00000000000000ff R14: 000055ed3b1f7be0 R15: 00007ffce3fc6960
 </TASK>
----------------
Code disassembly (best guess):
   0:	bd 00 00 00 00       	mov    $0x0,%ebp
   5:	00 fc                	add    %bh,%ah
   7:	ff                   	(bad)
   8:	df 80 3c 28 00 74    	filds  0x7400283c(%rax)
   e:	08 4c 89 ef          	or     %cl,-0x11(%rcx,%rcx,4)
  12:	e8 b3 da ca ff       	call   0xffcadaca
  17:	4d 8b 6d 00          	mov    0x0(%r13),%r13
  1b:	49 83 c5 68          	add    $0x68,%r13
  1f:	4c 89 e8             	mov    %r13,%rax
  22:	48 c1 e8 03          	shr    $0x3,%rax
  26:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1)
* 2a:	74 08                	je     0x34 <-- trapping instruction
  2c:	4c 89 ef             	mov    %r13,%rdi
  2f:	e8 96 da ca ff       	call   0xffcadaca
  34:	4d 8b 6d 00          	mov    0x0(%r13),%r13
  38:	4d 85 ed             	test   %r13,%r13
  3b:	74 53                	je     0x90
  3d:	e8                   	.byte 0xe8
  3e:	38                   	.byte 0x38
  3f:	94                   	xchg   %eax,%esp

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/07 13:14 linux-6.6.y 355bd0b51d2f d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING: ODEBUG bug in __run_timers
2025/09/06 01:03 linux-6.6.y 355bd0b51d2f d291dd2d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING: ODEBUG bug in __run_timers
* Struck through repros no longer work on HEAD.