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BUG: KASAN: use-after-free in hci_chan_del+0x33/0x130 net/bluetooth/hci_conn.c:1728
Read of size 8 at addr ffff88809398cd18 by task syz-executor.4/6880

CPU: 0 PID: 6880 Comm: syz-executor.4 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1d6/0x29e lib/dump_stack.c:118
 print_address_description+0x66/0x620 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report+0x132/0x1d0 mm/kasan/report.c:530
 hci_chan_del+0x33/0x130 net/bluetooth/hci_conn.c:1728
 l2cap_conn_del+0x4c2/0x650 net/bluetooth/l2cap_core.c:1900
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline]
 hci_conn_hash_flush+0x127/0x200 net/bluetooth/hci_conn.c:1557
 hci_dev_do_close+0xb7b/0x1040 net/bluetooth/hci_core.c:1770
 hci_unregister_dev+0x185/0x1590 net/bluetooth/hci_core.c:3790
 vhci_release+0x73/0xc0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x34f/0x7b0 fs/file_table.c:281
 task_work_run+0x137/0x1c0 kernel/task_work.c:141
 exit_task_work include/linux/task_work.h:25 [inline]
 do_exit+0x5f3/0x1f20 kernel/exit.c:806
 do_group_exit+0x161/0x2d0 kernel/exit.c:903
 __do_sys_exit_group+0x13/0x20 kernel/exit.c:914
 __se_sys_exit_group+0x10/0x10 kernel/exit.c:912
 __x64_sys_exit_group+0x37/0x40 kernel/exit.c:912
 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5f9
Code: Bad RIP value.
RSP: 002b:00007fff46742888 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000016 RCX: 000000000045d5f9
RDX: 0000000000416e81 RSI: 00000000016a85f0 RDI: 0000000000000000
RBP: 00000000004c210f R08: 000000000000000c R09: 0000000000000000
R10: 000000000201c940 R11: 0000000000000246 R12: 00007fff46743b30
R13: 0000000002025aa0 R14: 0000000000000000 R15: 00007fff46744bc0

Allocated by task 6888:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461
 kmem_cache_alloc_trace+0x1e4/0x2e0 mm/slab.c:3550
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 hci_chan_create+0x9a/0x270 net/bluetooth/hci_conn.c:1713
 l2cap_conn_add+0x66/0xb00 net/bluetooth/l2cap_core.c:7698
 l2cap_connect_cfm+0xdb/0x12b0 net/bluetooth/l2cap_core.c:8098
 hci_connect_cfm include/net/bluetooth/hci_core.h:1423 [inline]
 le_conn_complete_evt+0x88d/0x1380 net/bluetooth/hci_event.c:5190
 hci_le_conn_complete_evt net/bluetooth/hci_event.c:5215 [inline]
 hci_le_meta_evt net/bluetooth/hci_event.c:5915 [inline]
 hci_event_packet+0x16e3/0x17e10 net/bluetooth/hci_event.c:6192
 hci_rx_work+0x246/0xa20 net/bluetooth/hci_core.c:4889
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Freed by task 6888:
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_set_track+0x3d/0x70 mm/kasan/common.c:56
 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kfree+0x113/0x200 mm/slab.c:3756
 hci_disconn_loglink_complete_evt net/bluetooth/hci_event.c:5018 [inline]
 hci_event_packet+0x2018/0x17e10 net/bluetooth/hci_event.c:6213
 hci_rx_work+0x246/0xa20 net/bluetooth/hci_core.c:4889
 process_one_work+0x789/0xfc0 kernel/workqueue.c:2269
 worker_thread+0xaa4/0x1460 kernel/workqueue.c:2415
 kthread+0x37e/0x3a0 drivers/block/aoe/aoecmd.c:1234
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff88809398cd00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff88809398cd00, ffff88809398cd80)
The buggy address belongs to the page:
page:00000000c6f67108 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x9398c
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002589948 ffffea00027bb708 ffff8880aa440400
raw: 0000000000000000 ffff88809398c000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809398cc00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809398cc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809398cd00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88809398cd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809398ce00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
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