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BUG: KASAN: use-after-free in instrument_atomic_write include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:748 [inline]
BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:1116 [inline]
BUG: KASAN: use-after-free in sco_chan_del+0xe6/0x430 net/bluetooth/sco.c:149
Write of size 4 at addr ffff888092ba2010 by task syz-executor373/6891

CPU: 1 PID: 6891 Comm: syz-executor373 Not tainted 5.8.0-next-20200810-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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 check_memory_region_inline mm/kasan/generic.c:186 [inline]
 check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
 instrument_atomic_write include/linux/instrumented.h:71 [inline]
 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:748 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:1116 [inline]
 sco_chan_del+0xe6/0x430 net/bluetooth/sco.c:149
 __sco_sock_close+0x16e/0x5b0 net/bluetooth/sco.c:434
 sco_sock_close net/bluetooth/sco.c:448 [inline]
 sco_sock_release+0x69/0x290 net/bluetooth/sco.c:1053
 __sock_release+0xcd/0x280 net/socket.c:596
 sock_close+0x18/0x20 net/socket.c:1277
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:135
 exit_task_work include/linux/task_work.h:25 [inline]
 do_exit+0xb7d/0x29f0 kernel/exit.c:806
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x40b/0x1ee0 kernel/signal.c:2743
 arch_do_signal+0x82/0x2520 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:135 [inline]
 exit_to_user_mode_prepare+0x15d/0x1c0 kernel/entry/common.c:166
 syscall_exit_to_user_mode+0x59/0x2b0 kernel/entry/common.c:241
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446dc9
Code: Bad RIP value.
RSP: 002b:00007ffdb64a82d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000446dc9
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 00007ffdb64a8310 R08: 0000000000000002 R09: 00000000000000ff
R10: 0000000000000004 R11: 0000000000000246 R12: 000000000000f8fb
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6886:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
 kmem_cache_alloc_trace+0x16e/0x2c0 mm/slab.c:3550
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 hci_conn_add+0x53/0x1330 net/bluetooth/hci_conn.c:525
 hci_connect_sco+0x356/0x860 net/bluetooth/hci_conn.c:1283
 sco_connect net/bluetooth/sco.c:241 [inline]
 sco_sock_connect+0x308/0x980 net/bluetooth/sco.c:588
 __sys_connect_file+0x155/0x1a0 net/socket.c:1852
 __sys_connect+0x161/0x190 net/socket.c:1869
 __do_sys_connect net/socket.c:1879 [inline]
 __se_sys_connect net/socket.c:1876 [inline]
 __x64_sys_connect+0x6f/0xb0 net/socket.c:1876
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 6884:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
 __kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
 __cache_free mm/slab.c:3418 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3756
 device_release+0x71/0x200 drivers/base/core.c:1800
 kobject_cleanup lib/kobject.c:704 [inline]
 kobject_release lib/kobject.c:735 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x171/0x270 lib/kobject.c:752
 put_device+0x1b/0x30 drivers/base/core.c:3029
 hci_conn_del+0x27e/0x6a0 net/bluetooth/hci_conn.c:645
 hci_phy_link_complete_evt.isra.0+0x508/0x790 net/bluetooth/hci_event.c:4940
 hci_event_packet+0x4696/0x87a8 net/bluetooth/hci_event.c:6205
 hci_rx_work+0x22e/0xb50 net/bluetooth/hci_core.c:4889
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff888092ba2000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 16 bytes inside of
 4096-byte region [ffff888092ba2000, ffff888092ba3000)
The buggy address belongs to the page:
page:00000000450b3bde refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x92ba2
head:00000000450b3bde order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea00024d5988 ffffea0002491b88 ffff8880aa040900
raw: 0000000000000000 ffff888092ba2000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888092ba1f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888092ba1f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888092ba2000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff888092ba2080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888092ba2100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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