------------[ cut here ]------------ ODEBUG: free active (active state 0) object: ffff88805baaba78 object type: timer_list hint: br_ip6_multicast_port_query_expired+0x0/0x380 net/bridge/br_multicast.c:-1 WARNING: lib/debugobjects.c:632 at debug_print_object lib/debugobjects.c:629 [inline], CPU#0: rcuc/0/20 WARNING: lib/debugobjects.c:632 at __debug_check_no_obj_freed lib/debugobjects.c:1116 [inline], CPU#0: rcuc/0/20 WARNING: lib/debugobjects.c:632 at debug_check_no_obj_freed+0x405/0x550 lib/debugobjects.c:1146, CPU#0: rcuc/0/20 Modules linked in: CPU: 0 UID: 0 PID: 20 Comm: rcuc/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 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 57 34 82 fd 48 8b 44 24 20 4c 8b 4d 00 4c 89 ef 48 c7 c6 40 78 a6 8b 48 c7 c2 c0 7d a6 8b 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:ffffc90000197a90 EFLAGS: 00010246 RAX: ffffffff89f26b20 RBX: ffffffff998410e8 RCX: 0000000000000000 RDX: ffffffff8ba67dc0 RSI: ffffffff8ba67840 RDI: ffffffff8f7495c0 RBP: ffffffff8b4f58a0 R08: ffff88805baaba78 R09: ffffffff8b4f6be0 R10: dffffc0000000000 R11: ffffffff81b0b2a0 R12: ffff88805baabc00 R13: ffffffff8f7495c0 R14: ffff88805baab000 R15: ffff88805baaba78 FS: 0000000000000000(0000) GS:ffff888126339000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005568e5c01030 CR3: 000000002a424000 CR4: 00000000003526f0 Call Trace: slab_free_hook mm/slub.c:2616 [inline] slab_free mm/slub.c:6165 [inline] kfree+0x13a/0x6c0 mm/slub.c:6483 kobject_cleanup lib/kobject.c:689 [inline] kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x228/0x560 lib/kobject.c:737 rcu_do_batch kernel/rcu/tree.c:2617 [inline] rcu_core kernel/rcu/tree.c:2869 [inline] rcu_cpu_kthread+0x99e/0x1470 kernel/rcu/tree.c:2957 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 89 44 24 20 mov %eax,0x20(%rsp) 4: e8 57 34 82 fd call 0xfd823460 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 40 78 a6 8b mov $0xffffffff8ba67840,%rsi 1c: 48 c7 c2 c0 7d a6 8b mov $0xffffffff8ba67dc0,%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