[v6.6] WARNING: ODEBUG bug in handle_softirqs

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: cbb31f77b879 Linux 6.6.121
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=127aa93a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=2a950bf7c0bff9f9
dashboard link: https://syzkaller.appspot.com/bug?extid=474a0f95923afb446ae8
compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6436cbae3604/disk-cbb31f77.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/8f3a3d318f99/vmlinux-cbb31f77.xz
kernel image: https://storage.googleapis.com/syzbot-assets/84920a2a012f/bzImage-cbb31f77.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+474a0f...@syzkaller.appspotmail.com

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ODEBUG: free active (active state 0) object: ffff888030560278 object type: timer_list hint: br_ip6_multicast_port_query_expired+0x0/0x20
WARNING: CPU: 0 PID: 12657 at lib/debugobjects.c:518 debug_print_object lib/debugobjects.c:515 [inline]
WARNING: CPU: 0 PID: 12657 at lib/debugobjects.c:518 __debug_check_no_obj_freed lib/debugobjects.c:990 [inline]
WARNING: CPU: 0 PID: 12657 at lib/debugobjects.c:518 debug_check_no_obj_freed+0x446/0x540 lib/debugobjects.c:1020
Modules linked in:
CPU: 0 PID: 12657 Comm: kworker/u4:8 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
Workqueue: bat_events batadv_nc_worker
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 a0 8a 1c 8b 48 c7 c6 00 87 1c 8b 48 c7 c2 20 8c 1c 8b 8b 0c 24 4d 89 f8 41 55 e8 3e 56 20 fd 48 83 c4 08 <0f> 0b 4c 8b 6c 24 18 48 b9 00 00 00 00 00 fc ff df ff 05 73 8d 5a
RSP: 0018:ffffc90000007af8 EFLAGS: 00010282
RAX: 0aa892bc0321b200 RBX: ffffffff97561fd0 RCX: ffff88802b470000
RDX: 0000000000000100 RSI: 0000000000000000 RDI: 0000000000000002
RBP: ffffffff8accab20 R08: ffffc900000076e7 R09: 1ffff92000000edc
R10: dffffc0000000000 R11: fffff52000000edd R12: ffff888030560400
R13: ffffffff89613390 R14: ffff888030560000 R15: ffff888030560278
FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0993be8600 CR3: 0000000066e17000 CR4: 00000000003506f0
DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083
DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
<IRQ>
slab_free_hook mm/slub.c:1786 [inline]
slab_free_freelist_hook+0xd2/0x1a0 mm/slub.c:1837
slab_free mm/slub.c:3830 [inline]
__kmem_cache_free+0xba/0x1e0 mm/slub.c:3843
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x221/0x460 lib/kobject.c:737
rcu_do_batch kernel/rcu/tree.c:2194 [inline]
rcu_core+0xcfb/0x1770 kernel/rcu/tree.c:2467
handle_softirqs+0x280/0x820 kernel/softirq.c:578
do_softirq+0xfa/0x1a0 kernel/softirq.c:479
</IRQ>
<TASK>
__local_bh_enable_ip+0x184/0x1c0 kernel/softirq.c:406
spin_unlock_bh include/linux/spinlock.h:396 [inline]
batadv_nc_purge_paths+0x311/0x3a0 net/batman-adv/network-coding.c:471
batadv_nc_worker+0x328/0x610 net/batman-adv/network-coding.c:720
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa5d/0x15d0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
</TASK>


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