==================================================================
BUG: KASAN: slab-use-after-free in __mutex_lock+0x801/0x1350
Read of size 8 at addr ffff88810672c0a0 by task khidpd_16bf5505/6016

CPU: 1 UID: 0 PID: 6016 Comm: khidpd_16bf5505 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xca/0x240
 kasan_report+0x118/0x150
 __mutex_lock+0x801/0x1350
 l2cap_unregister_user+0x6a/0x1b0
 hidp_session_thread+0x3c9/0x410
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 13270:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x411/0x7f0
 hci_alloc_dev_priv+0x28/0x2060
 vhci_create_device+0x120/0x650
 vhci_write+0x3ce/0x4a0
 vfs_write+0x5c9/0xb30
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 8171:
 kasan_save_track+0x3e/0x80
 __kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x19a/0x6d0
 bt_host_release+0x82/0x90
 device_release+0x9c/0x1c0
 kobject_put+0x22b/0x480
 vhci_release+0x15a/0x1a0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x2300
 do_group_exit+0x21c/0x2d0
 get_signal+0x1285/0x1340
 arch_do_signal_or_restart+0xa0/0x790
 exit_to_user_mode_loop+0x72/0x130
 do_syscall_64+0x2bd/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 insert_work+0x3d/0x330
 __queue_work+0xcd2/0xfb0
 queue_work_on+0x181/0x270
 __hci_cmd_sync_sk+0x4d4/0xbc0
 hci_inquiry_sync+0x1d1/0x3a0
 hci_inquiry+0x388/0x610
 sock_do_ioctl+0xdc/0x300
 sock_ioctl+0x576/0x790
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 insert_work+0x3d/0x330
 __queue_work+0xcd2/0xfb0
 queue_work_on+0x181/0x270
 hci_cmd_sync_submit+0x285/0x2b0
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x4bc/0x870
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88810672c000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 160 bytes inside of
 freed 8192-byte region [ffff88810672c000, ffff88810672e000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106728
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
ksm flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888100042280 ffffea0004822400 dead000000000003
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888100042280 ffffea0004822400 dead000000000003
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 017ff00000000003 ffffea000419ca01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 11736, tgid 11735 (syz.1.1483), ts 228085415893, free_ts 226779345588
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x2365/0x2440
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x96/0x350
 ___slab_alloc+0xf56/0x1990
 __slab_alloc+0x65/0x100
 __kmalloc_node_track_caller_noprof+0x5c7/0x800
 kmalloc_reserve+0x136/0x290
 __alloc_skb+0x142/0x2d0
 netlink_dump+0x167/0xe90
 netlink_recvmsg+0x676/0xa30
 sock_recvmsg_nosec+0x186/0x1c0
 ____sys_recvmsg+0x3aa/0x460
 ___sys_recvmsg+0x1b5/0x510
 do_recvmmsg+0x307/0x770
page last free pid 5247 tgid 5247 stack trace:
 __free_frozen_pages+0xbc4/0xd30
 __put_partials+0x146/0x170
 put_cpu_partial+0x1f2/0x2e0
 __slab_free+0x2b9/0x390
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_node_noprof+0x433/0x710
 __alloc_skb+0x112/0x2d0
 alloc_skb_with_frags+0xca/0x890
 sock_alloc_send_pskb+0x84d/0x980
 unix_dgram_sendmsg+0x461/0x1850
 __sock_sendmsg+0x21c/0x270
 __sys_sendto+0x3bd/0x520
 __x64_sys_sendto+0xde/0x100
 do_syscall_64+0xfa/0xfa0

Memory state around the buggy address:
 ffff88810672bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810672c000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88810672c080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88810672c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810672c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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