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BUG: KASAN: slab-use-after-free in hci_conn_drop+0x34/0x2a0
Write of size 4 at addr ffff88810aeac010 by task kworker/u11:0/56

CPU: 0 UID: 0 PID: 56 Comm: kworker/u11:0 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
Workqueue: hci0 hci_cmd_sync_work
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_report+0xba/0x230
 kasan_report+0x117/0x150
 kasan_check_range+0x264/0x2c0
 hci_conn_drop+0x34/0x2a0
 hci_cmd_sync_work+0x25a/0x3f0
 process_scheduled_works+0xa2f/0x1470
 worker_thread+0xa44/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30
 </TASK>

Allocated by task 5602:
 kasan_save_track+0x3e/0x80
 __kasan_kmalloc+0x93/0xb0
 __kmalloc_cache_noprof+0x318/0x660
 __hci_conn_add+0x3c4/0x1dd0
 le_conn_complete_evt+0x6bc/0x1360
 hci_le_enh_conn_complete_evt+0x189/0x490
 hci_event_packet+0x7af/0x12a0
 hci_rx_work+0x3ee/0x1010
 process_scheduled_works+0xa2f/0x1470
 worker_thread+0xa44/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

Freed by task 5602:
 kasan_save_track+0x3e/0x80
 kasan_save_free_info+0x40/0x50
 __kasan_slab_free+0x5c/0x80
 kfree+0x1c1/0x630
 device_release+0x9e/0x1d0
 kobject_put+0x222/0x550
 hci_conn_del+0xc3d/0x1200
 hci_disconn_complete_evt+0x64f/0x940
 hci_event_packet+0x803/0x12a0
 hci_rx_work+0x3ee/0x1010
 process_scheduled_works+0xa2f/0x1470
 worker_thread+0xa44/0xfb0
 kthread+0x388/0x470
 ret_from_fork+0x51e/0xb90
 ret_from_fork_asm+0x1a/0x30

The buggy address belongs to the object at ffff88810aeac000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 16 bytes inside of
 freed 8192-byte region [ffff88810aeac000, ffff88810aeae000)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10aea8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x17ff00000000040(head|node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 017ff00000000040 ffff888100042280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 017ff00000000040 ffff888100042280 dead000000000100 dead000000000122
head: 0000000000000000 0000000800020002 00000000f5000000 0000000000000000
head: 017ff00000000003 ffffea00042baa01 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 5517, tgid 5517 (sshd), ts 44448193628, free_ts 44383694619
 post_alloc_hook+0x231/0x280
 get_page_from_freelist+0x2503/0x25a0
 __alloc_frozen_pages_noprof+0x18d/0x380
 allocate_slab+0x77/0x660
 refill_objects+0x32e/0x3c0
 __pcs_replace_empty_main+0x2f9/0x5e0
 __kmalloc_node_track_caller_noprof+0x565/0x7b0
 __alloc_skb+0x2bd/0x7a0
 netlink_dump+0x190/0xf30
 netlink_recvmsg+0x683/0xa50
 sock_recvmsg+0x172/0x1b0
 ____sys_recvmsg+0x1e6/0x4a0
 ___sys_recvmsg+0x213/0x590
 __x64_sys_recvmsg+0x1ba/0x2a0
 do_syscall_64+0x170/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5515 tgid 5515 stack trace:
 __free_frozen_pages+0xc14/0xda0
 __slab_free+0x263/0x2b0
 qlist_free_all+0x98/0x100
 kasan_quarantine_reduce+0x148/0x160
 __kasan_slab_alloc+0x22/0x80
 __kmalloc_noprof+0x312/0x750
 load_elf_binary+0x2c3/0x2950
 bprm_execve+0x9c3/0x1580
 do_execveat_common+0x4f1/0x670
 __x64_sys_execve+0x97/0xc0
 do_syscall_64+0x170/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88810aeabf00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88810aeabf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88810aeac000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff88810aeac080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88810aeac100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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