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BUG: KASAN: use-after-free in hci_chan_del+0x13e/0x180 net/bluetooth/hci_conn.c:1666
Read of size 8 at addr ffff888090e74f18 by task syz-executor.5/6496

CPU: 1 PID: 6496 Comm: syz-executor.5 Not tainted 4.19.136-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+0x1fc/0x2fe lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1c7 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 hci_chan_del+0x13e/0x180 net/bluetooth/hci_conn.c:1666
 l2cap_conn_del+0x44f/0x6b0 net/bluetooth/l2cap_core.c:1736
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7435 [inline]
 l2cap_disconn_cfm+0x85/0xa0 net/bluetooth/l2cap_core.c:7428
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1261 [inline]
 hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1495
 hci_dev_do_close+0x624/0xe70 net/bluetooth/hci_core.c:1666
 hci_unregister_dev+0x17c/0x7f0 net/bluetooth/hci_core.c:3271
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:354
 __fput+0x2ce/0x890 fs/file_table.c:278
 task_work_run+0x148/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xbb2/0x2b70 kernel/exit.c:887
 do_group_exit+0x125/0x310 kernel/exit.c:990
 __do_sys_exit_group kernel/exit.c:1001 [inline]
 __se_sys_exit_group kernel/exit.c:999 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:999
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45ccd9
Code: Bad RIP value.
RSP: 002b:00007ffef8d635e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000045ccd9
RDX: 0000000000416731 RSI: 0000000000ca85f0 RDI: 0000000000000043
RBP: 00000000004c2963 R08: 000000000000000b R09: 0000000000000000
R10: 00000000010d6940 R11: 0000000000000246 R12: 0000000000000005
R13: 00007ffef8d63730 R14: 0000000000162c79 R15: 00007ffef8d63740

Allocated by task 6528:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 sock_alloc_inode+0x5f/0x250 net/socket.c:247
 alloc_inode+0x5d/0x180 fs/inode.c:211
 new_inode_pseudo+0x14/0xe0 fs/inode.c:911
 sock_alloc+0x3c/0x260 net/socket.c:547
 __sock_create+0xba/0x740 net/socket.c:1240
 sock_create net/socket.c:1316 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1346
 __do_sys_socket net/socket.c:1355 [inline]
 __se_sys_socket net/socket.c:1353 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1353
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 18:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 __rcu_reclaim kernel/rcu/rcu.h:231 [inline]
 rcu_do_batch kernel/rcu/tree.c:2584 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
 rcu_process_callbacks+0xa0d/0x18b0 kernel/rcu/tree.c:2881
 __do_softirq+0x26c/0x9a0 kernel/softirq.c:292

The buggy address belongs to the object at ffff888090e74f00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff888090e74f00, ffff888090e74f80)
The buggy address belongs to the page:
page:ffffea0002439d00 count:1 mapcount:0 mapping:ffff88812c39c640 index:0xffff888090e74a80
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea0002185108 ffffea00021138c8 ffff88812c39c640
raw: ffff888090e74a80 ffff888090e74000 0000000100000013 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888090e74e00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff888090e74e80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff888090e74f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888090e74f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888090e75000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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