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BUG: KASAN: slab-use-after-free in __mutex_lock+0x738/0xe80
Read of size 8 at addr ffff888028de80a0 by task khidpd_16c05505/8232

CPU: 0 UID: 0 PID: 8232 Comm: khidpd_16c05505 Not tainted 6.16.0-rc5-syzkaller-00159-g47c84997c686 #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+0xd2/0x2b0
 kasan_report+0x118/0x150
 __mutex_lock+0x738/0xe80
 l2cap_unregister_user+0x6a/0x1b0
 hidp_session_thread+0x3c9/0x410
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 5851:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_noprof+0x27a/0x4f0
 hci_alloc_dev_priv+0x28/0x2040
 vhci_create_device+0x120/0x6e0
 vhci_write+0x3ce/0x4a0
 vfs_write+0x54b/0xa90
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5851:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x62/0x70
 kfree+0x18e/0x440
 bt_host_release+0x82/0x90
 device_release+0x9c/0x1c0
 kobject_put+0x22b/0x480
 vhci_release+0x88/0xd0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x22e0
 do_group_exit+0x21c/0x2d0
 get_signal+0x1286/0x1340
 arch_do_signal_or_restart+0x9a/0x750
 exit_to_user_mode_loop+0x75/0x110
 do_syscall_64+0x2bd/0x3b0
 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+0xcfc/0xfe0
 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+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30

Second to last potentially related work creation:
 kasan_save_stack+0x3e/0x60
 kasan_record_aux_stack+0xbd/0xd0
 insert_work+0x3d/0x330
 __queue_work+0xcfc/0xfe0
 queue_work_on+0x181/0x270
 l2cap_chan_send+0x1110/0x2790
 l2cap_sock_sendmsg+0x32e/0x4a0
 __sock_sendmsg+0x21c/0x270
 sock_sendmsg+0x158/0x230
 splice_to_socket+0x8ff/0xf10
 do_splice+0xc79/0x1660
 __se_sys_splice+0x2e1/0x460
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888028de8000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 160 bytes inside of
 freed 8192-byte region [ffff888028de8000, ffff888028dea000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x28de8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801a442280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000040 ffff88801a442280 dead000000000122 0000000000000000
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 00fff00000000003 ffffea0000a37a01 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 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5851, tgid 5851 (syz-executor), ts 54381353118, free_ts 54113262490
 post_alloc_hook+0x240/0x2a0
 get_page_from_freelist+0x21e4/0x22c0
 __alloc_frozen_pages_noprof+0x181/0x370
 alloc_pages_mpol+0x232/0x4a0
 allocate_slab+0x8a/0x3b0
 ___slab_alloc+0xbfc/0x1480
 __kmalloc_noprof+0x305/0x4f0
 hci_alloc_dev_priv+0x28/0x2040
 vhci_create_device+0x120/0x6e0
 vhci_write+0x3ce/0x4a0
 vfs_write+0x54b/0xa90
 ksys_write+0x145/0x250
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5833 tgid 5833 stack trace:
 __free_frozen_pages+0xc71/0xe70
 __put_partials+0x161/0x1c0
 put_cpu_partial+0x17c/0x250
 __slab_free+0x2f7/0x400
 qlist_free_all+0x97/0x140
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 kmem_cache_alloc_noprof+0x1c1/0x3c0
 jbd2__journal_start+0x146/0x5b0
 __ext4_journal_start_sb+0x227/0x5c0
 __ext4_unlink+0x3dc/0xab0
 ext4_unlink+0x216/0x5d0
 vfs_unlink+0x394/0x650
 do_unlinkat+0x350/0x560
 __x64_sys_unlink+0x47/0x50
 do_syscall_64+0xfa/0x3b0

Memory state around the buggy address:
 ffff888028de7f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888028de8000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888028de8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff888028de8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888028de8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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