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BUG: KASAN: slab-use-after-free in __mutex_lock+0x738/0xe80
Read of size 8 at addr ffff88811b1e9b20 by task kworker/1:2/96

CPU: 1 UID: 0 PID: 96 Comm: kworker/1:2 Not tainted 6.16.0-rc5-syzkaller-00159-g47c84997c686-dirty #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Workqueue: events l2cap_chan_timeout
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 print_report+0xd2/0x2b0
 kasan_report+0x118/0x150
 __mutex_lock+0x738/0xe80
 l2cap_chan_timeout+0x63/0x390
 process_scheduled_works+0xae1/0x17b0
 worker_thread+0x8a0/0xda0
 kthread+0x711/0x8a0
 ret_from_fork+0x3fc/0x770
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 7996:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x230/0x3d0
 l2cap_conn_add+0xaa/0x8d0
 l2cap_chan_connect+0x6c8/0xe30
 l2cap_sock_connect+0x5c5/0x7a0
 kernel_connect+0x116/0x180
 rfcomm_dlc_open+0x8fe/0xed0
 rfcomm_sock_connect+0x2f7/0x610
 __sys_connect+0x316/0x440
 __x64_sys_connect+0x7a/0x90
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 7859:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x46/0x50
 __kasan_slab_free+0x62/0x70
 kfree+0x18e/0x440
 hci_conn_hash_flush+0x10d/0x230
 hci_dev_close_sync+0xaef/0x1330
 hci_unregister_dev+0x21a/0x510
 vhci_release+0x80/0xd0
 __fput+0x44c/0xa70
 task_work_run+0x1d4/0x260
 do_exit+0x6b5/0x22e0
 do_group_exit+0x21c/0x2d0
 __x64_sys_exit_group+0x3f/0x40
 x64_sys_call+0x21ba/0x21c0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88811b1e9800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 800 bytes inside of
 freed 1024-byte region [ffff88811b1e9800, ffff88811b1e9c00)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff88811b1ed000 pfn:0x11b1e8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x57ff00000000240(workingset|head|node=1|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 057ff00000000240 ffff88801a441dc0 ffffea00046ee210 ffffea000422a410
raw: ffff88811b1ed000 000000000010000e 00000000f5000000 0000000000000000
head: 057ff00000000240 ffff88801a441dc0 ffffea00046ee210 ffffea000422a410
head: ffff88811b1ed000 000000000010000e 00000000f5000000 0000000000000000
head: 057ff00000000003 ffffea00046c7a01 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 7644, tgid 7644 (dhcpcd-run-hook), ts 100479158057, free_ts 100467368704
 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
 load_elf_phdrs+0x139/0x230
 load_elf_binary+0x920/0x2790
 bprm_execve+0x99c/0x1450
 do_execveat_common+0x510/0x6a0
 __x64_sys_execve+0x94/0xb0
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 7643 tgid 7643 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
 getname_flags+0xb8/0x540
 do_sys_openat2+0xbc/0x1c0
 __x64_sys_openat+0x138/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88811b1e9a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811b1e9a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88811b1e9b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                               ^
 ffff88811b1e9b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88811b1e9c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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