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BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:963 [inline]
BUG: KASAN: use-after-free in sco_chan_del+0x3b2/0x3d0 net/bluetooth/sco.c:148
Read of size 1 at addr ffff8880a87baef5 by task syz-executor683/13564

CPU: 0 PID: 13564 Comm: syz-executor683 Not tainted 4.14.193-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load1_noabort+0x68/0x70 mm/kasan/report.c:427
 hci_conn_drop include/net/bluetooth/hci_core.h:963 [inline]
 sco_chan_del+0x3b2/0x3d0 net/bluetooth/sco.c:148
 __sco_sock_close+0xb0/0x670 net/bluetooth/sco.c:433
 sco_sock_close net/bluetooth/sco.c:447 [inline]
 sco_sock_release+0x6a/0x370 net/bluetooth/sco.c:1009
 __sock_release+0xcd/0x2b0 net/socket.c:602
 sock_close+0x15/0x20 net/socket.c:1139
 __fput+0x25f/0x7a0 fs/file_table.c:210
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0xa08/0x27f0 kernel/exit.c:865
 do_group_exit+0x100/0x2e0 kernel/exit.c:962
 get_signal+0x38d/0x1ca0 kernel/signal.c:2423
 do_signal+0x7c/0x1550 arch/x86/kernel/signal.c:814
 exit_to_usermode_loop+0x160/0x200 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x446f29
RSP: 002b:00007ffd389a8358 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000446f29
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 000000000000c97d R08: 0000000000000002 R09: 00000000000500ff
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000407b80 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 13564:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 hci_conn_add+0x53/0x12f0 net/bluetooth/hci_conn.c:501
 hci_connect_sco+0x265/0x7d0 net/bluetooth/hci_conn.c:1119
 sco_connect net/bluetooth/sco.c:240 [inline]
 sco_sock_connect+0x26c/0x860 net/bluetooth/sco.c:576
 SYSC_connect net/socket.c:1655 [inline]
 SyS_connect+0x1f4/0x240 net/socket.c:1636
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 1201:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 device_release+0xf0/0x1a0 drivers/base/core.c:831
 kobject_cleanup lib/kobject.c:646 [inline]
 kobject_release lib/kobject.c:675 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x1f3/0x2d0 lib/kobject.c:692
 put_device+0x1c/0x30 drivers/base/core.c:2014
 hci_conn_del+0x235/0x620 net/bluetooth/hci_conn.c:611
 hci_phy_link_complete_evt.isra.0+0x4d0/0x6c0 net/bluetooth/hci_event.c:4355
 hci_event_packet+0x2592/0x7c7a net/bluetooth/hci_event.c:5429
 hci_rx_work+0x3e6/0x970 net/bluetooth/hci_core.c:4244
 process_one_work+0x793/0x14a0 kernel/workqueue.c:2116
 worker_thread+0x5cc/0xff0 kernel/workqueue.c:2250
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404

The buggy address belongs to the object at ffff8880a87baec0
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 53 bytes inside of
 4096-byte region [ffff8880a87baec0, ffff8880a87bbec0)
The buggy address belongs to the page:
page:ffffea0002a1ee80 count:1 mapcount:0 mapping:ffff8880a87baec0 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a87baec0 0000000000000000 0000000100000001
raw: ffffea00029e4c20 ffffea00029e4920 ffff88812fe52dc0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a87bad80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a87bae00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a87bae80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                             ^
 ffff8880a87baf00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a87baf80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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