==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:182
Read of size 1 at addr ffff0000d44875a0 by task syz-executor/4724

CPU: 1 UID: 0 PID: 4724 Comm: syz-executor Tainted: G             L      syzkaller #0 PREEMPT 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 __kasan_check_byte+0x3c/0x54 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0xa4/0x364 kernel/locking/lockdep.c:5842
 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:150 [inline]
 _raw_spin_lock_bh+0x48/0x60 kernel/locking/spinlock.c:182
 spin_lock_bh include/linux/spinlock.h:348 [inline]
 bt_accept_unlink+0x5c/0x28c net/bluetooth/af_bluetooth.c:262
 l2cap_sock_teardown_cb+0x148/0x38c net/bluetooth/l2cap_sock.c:1710
 l2cap_chan_del+0x9c/0x4bc net/bluetooth/l2cap_core.c:687
 l2cap_conn_del+0x288/0x408 net/bluetooth/l2cap_core.c:1825
 l2cap_disconn_cfm+0x90/0x100 net/bluetooth/l2cap_core.c:7601
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
 hci_conn_hash_flush+0x108/0x238 net/bluetooth/hci_conn.c:2735
 hci_dev_close_sync+0x5e0/0xe38 net/bluetooth/hci_sync.c:5513
 hci_dev_do_close+0x34/0xbc net/bluetooth/hci_core.c:499
 hci_unregister_dev+0x1fc/0x4bc net/bluetooth/hci_core.c:2678
 vhci_release+0x12c/0x17c drivers/bluetooth/hci_vhci.c:700
 __fput+0x338/0x74c fs/file_table.c:512
 ____fput+0x20/0x30 fs/file_table.c:540
 task_work_run+0x1cc/0x25c kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x58c/0x1a74 kernel/exit.c:1009
 do_group_exit+0x198/0x238 kernel/exit.c:1152
 __do_sys_exit_group kernel/exit.c:1163 [inline]
 __se_sys_exit_group kernel/exit.c:1161 [inline]
 pid_child_should_wake+0x0/0x104 kernel/exit.c:1161
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

Allocated by task 8921:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_node_noprof+0x438/0x6d8 mm/slub.c:5346
 _kmalloc_node_noprof include/linux/slab.h:1197 [inline]
 qdisc_alloc+0x8c/0x7b0 net/sched/sch_generic.c:998
 qdisc_create_dflt+0x9c/0x570 net/sched/sch_generic.c:1053
 mq_init_common+0x254/0x438 net/sched/sch_mq.c:91
 mq_init+0x2c/0x6c net/sched/sch_mq.c:112
 qdisc_create_dflt+0x120/0x570 net/sched/sch_generic.c:1060
 attach_default_qdiscs net/sched/sch_generic.c:1242 [inline]
 dev_activate+0x1a4/0xc4c net/sched/sch_generic.c:1296
 __dev_open+0x554/0x76c net/core/dev.c:1711
 __dev_change_flags+0x294/0x698 net/core/dev.c:9760
 netif_change_flags+0x80/0x15c net/core/dev.c:9823
 dev_change_flags+0x10c/0x204 net/core/dev_api.c:68
 dev_ifsioc+0x350/0xc34 net/core/dev_ioctl.c:555
 dev_ioctl+0x444/0xc88 net/core/dev_ioctl.c:816
 sock_do_ioctl+0x198/0x254 net/socket.c:1314
 sock_ioctl+0x55c/0x7ec net/socket.c:1421
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x154/0x1cc fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

Freed by task 23:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_free_info+0x54/0x6c mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x74/0xa4 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2677 [inline]
 slab_free mm/slub.c:6377 [inline]
 kfree+0x188/0x690 mm/slub.c:6692
 qdisc_free+0xac/0xd0 net/sched/sch_generic.c:1096
 qdisc_free_cb+0x20/0x30 net/sched/sch_generic.c:1103
 rcu_do_batch kernel/rcu/tree.c:2645 [inline]
 rcu_core+0x598/0xf04 kernel/rcu/tree.c:2897
 rcu_core_si+0x10/0x1c kernel/rcu/tree.c:2914
 handle_softirqs+0x2ec/0xd98 kernel/softirq.c:622
 run_ksoftirqd+0x70/0xbc kernel/softirq.c:1076
 smpboot_thread_fn+0x4e4/0x97c kernel/smpboot.c:160
 kthread+0x304/0x3d4 kernel/kthread.c:436
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838

Last potentially related work creation:
 kasan_save_stack+0x40/0x6c mm/kasan/common.c:57
 kasan_record_aux_stack+0xb0/0xc8 mm/kasan/generic.c:556
 __call_rcu_common kernel/rcu/tree.c:3159 [inline]
 call_rcu+0x104/0x75c kernel/rcu/tree.c:3279
 __qdisc_destroy+0x2fc/0x634 net/sched/sch_generic.c:1130
 qdisc_put+0x90/0x120 net/sched/sch_generic.c:1150
 shutdown_scheduler_queue+0x10c/0x12c net/sched/sch_generic.c:1203
 netdev_for_each_tx_queue include/linux/netdevice.h:2737 [inline]
 dev_shutdown+0xa4/0x368 net/sched/sch_generic.c:1512
 unregister_netdevice_many_notify+0xc08/0x1760 net/core/dev.c:12435
 unregister_netdevice_many net/core/dev.c:12509 [inline]
 unregister_netdevice_queue+0x274/0x30c net/core/dev.c:12320
 unregister_netdevice include/linux/netdevice.h:3474 [inline]
 __tun_detach+0x814/0xec8 drivers/net/tun.c:621
 tun_detach drivers/net/tun.c:637 [inline]
 tun_chr_close+0x118/0x1f4 drivers/net/tun.c:3442
 __fput+0x338/0x74c fs/file_table.c:512
 ____fput+0x20/0x30 fs/file_table.c:540
 task_work_run+0x1cc/0x25c 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:70 [inline]
 exit_to_user_mode_loop+0x10c/0x17c kernel/entry/common.c:101
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
 arm64_syscall_exit_to_user_mode arch/arm64/kernel/entry-common.c:108 [inline]
 el0_svc+0x18c/0x260 arch/arm64/kernel/entry-common.c:759
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

The buggy address belongs to the object at ffff0000d4487000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1440 bytes inside of
 freed 2048-byte region [ffff0000d4487000, ffff0000d4487800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x114480
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x5ffc00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000040 ffff0000c0002000 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 05ffc00000000040 ffff0000c0002000 dead000000000100 dead000000000122
head: 0000000000000000 0000000800080008 00000000f5000000 0000000000000000
head: 05ffc00000000003 fffffdffc3512001 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000d4487480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d4487500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff0000d4487580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff0000d4487600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff0000d4487680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
 slab kmalloc-2k start ffff0000d4487000 pointer offset 1400 size 2048
list_del corruption. prev->next should be ffff0000c9b2a578, but was 0000000000000000. (prev=ffff0000d4487578)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:64!
Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 4724 Comm: syz-executor Tainted: G    B        L      syzkaller #0 PREEMPT 
Tainted: [B]=BAD_PAGE, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/07/2026
pstate: 63400005 (nZCv daif +PAN -UAO +TCO +DIT -SSBS BTYPE=--)
pc : __list_del_entry_valid_or_report+0x180/0x1b8 lib/list_debug.c:62
lr : __list_del_entry_valid_or_report+0x180/0x1b8 lib/list_debug.c:62
sp : ffff800096127690
x29: ffff800096127690 x28: ffff0000dc132a88 x27: ffff0000dc132a88
x26: ffff0000d41f000c x25: ffff0000c9b2a19c x24: ffff0000c9b2a578
x23: 1fffe0001a890eaf x22: dfff800000000000 x21: ffff0000d4487578
x20: ffff0000d4487578 x19: ffff0000c9b2a578 x18: 1fffe00034bbbe28
x17: 20747562202c3837 x16: 3561326239633030 x15: 3030666666662065
x14: 6220646c756f6873 x13: 0000000000000001 x12: 0000000000000000
x11: 0000000000000000 x10: 0000000000000202 x9 : 66d58d8ec26b3800
x8 : 66d58d8ec26b3800 x7 : 0000000000000000 x6 : ffff80008048c5b8
x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff8000804972c8
x2 : 0000000100000201 x1 : ffff0000d364ba80 x0 : 000000000000006d
Call trace:
 __list_del_entry_valid_or_report+0x180/0x1b8 lib/list_debug.c:62 (P)
 __list_del_entry_valid include/linux/list.h:132 [inline]
 __list_del_entry include/linux/list.h:246 [inline]
 list_del_init include/linux/list.h:318 [inline]
 bt_accept_unlink+0x68/0x28c net/bluetooth/af_bluetooth.c:263
 l2cap_sock_teardown_cb+0x148/0x38c net/bluetooth/l2cap_sock.c:1710
 l2cap_chan_del+0x9c/0x4bc net/bluetooth/l2cap_core.c:687
 l2cap_conn_del+0x288/0x408 net/bluetooth/l2cap_core.c:1825
 l2cap_disconn_cfm+0x90/0x100 net/bluetooth/l2cap_core.c:7601
 hci_disconn_cfm include/net/bluetooth/hci_core.h:2154 [inline]
 hci_conn_hash_flush+0x108/0x238 net/bluetooth/hci_conn.c:2735
 hci_dev_close_sync+0x5e0/0xe38 net/bluetooth/hci_sync.c:5513
 hci_dev_do_close+0x34/0xbc net/bluetooth/hci_core.c:499
 hci_unregister_dev+0x1fc/0x4bc net/bluetooth/hci_core.c:2678
 vhci_release+0x12c/0x17c drivers/bluetooth/hci_vhci.c:700
 __fput+0x338/0x74c fs/file_table.c:512
 ____fput+0x20/0x30 fs/file_table.c:540
 task_work_run+0x1cc/0x25c kernel/task_work.c:233
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x58c/0x1a74 kernel/exit.c:1009
 do_group_exit+0x198/0x238 kernel/exit.c:1152
 __do_sys_exit_group kernel/exit.c:1163 [inline]
 __se_sys_exit_group kernel/exit.c:1161 [inline]
 pid_child_should_wake+0x0/0x104 kernel/exit.c:1161
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:758
 el0t_64_sync_handler+0x44/0x104 arch/arm64/kernel/entry-common.c:777
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590
Code: 91308000 aa1303e1 aa1503e3 979c2c42 (d4210000) 
---[ end trace 0000000000000000 ]---