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BUG: KASAN: use-after-free in atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline]
BUG: KASAN: use-after-free in hci_conn_drop include/net/bluetooth/hci_core.h:972 [inline]
BUG: KASAN: use-after-free in sco_chan_del+0xe6/0x420 net/bluetooth/sco.c:148
Write of size 4 at addr ffff8880a1256210 by task syz-executor367/6645

CPU: 1 PID: 6645 Comm: syz-executor367 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+0x8f/0x96 mm/kasan/report.c:412
 atomic_dec_and_test include/asm-generic/atomic-instrumented.h:259 [inline]
 hci_conn_drop include/net/bluetooth/hci_core.h:972 [inline]
 sco_chan_del+0xe6/0x420 net/bluetooth/sco.c:148
 __sco_sock_close+0xc3/0x720 net/bluetooth/sco.c:433
 sco_sock_close net/bluetooth/sco.c:447 [inline]
 sco_sock_release+0x6b/0x3d0 net/bluetooth/sco.c:1008
 __sock_release+0xcd/0x2a0 net/socket.c:579
 sock_close+0x15/0x20 net/socket.c:1140
 __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
 get_signal+0x3f2/0x1f70 kernel/signal.c:2588
 do_signal+0x8f/0x1670 arch/x86/kernel/signal.c:821
 exit_to_usermode_loop+0x204/0x2a0 arch/x86/entry/common.c:163
 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
 do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x446e69
Code: Bad RIP value.
RSP: 002b:00007fff82f03958 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: fffffffffffffffc RBX: 0000000000000003 RCX: 0000000000446e69
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000002 R09: 00000003000100ff
R10: 0000000000000004 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000407ac0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 6645:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 kzalloc include/linux/slab.h:709 [inline]
 hci_conn_add+0x53/0x11e0 net/bluetooth/hci_conn.c:501
 hci_connect_sco+0x2fc/0x950 net/bluetooth/hci_conn.c:1238
 sco_connect net/bluetooth/sco.c:240 [inline]
 sco_sock_connect+0x2ff/0x970 net/bluetooth/sco.c:576
 __sys_connect+0x265/0x2c0 net/socket.c:1663
 __do_sys_connect net/socket.c:1674 [inline]
 __se_sys_connect net/socket.c:1671 [inline]
 __x64_sys_connect+0x6f/0xb0 net/socket.c:1671
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6641:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 device_release+0x76/0x210 drivers/base/core.c:1061
 kobject_cleanup lib/kobject.c:662 [inline]
 kobject_release lib/kobject.c:691 [inline]
 kref_put include/linux/kref.h:70 [inline]
 kobject_put+0x22d/0x350 lib/kobject.c:708
 put_device+0x1c/0x30 drivers/base/core.c:2251
 hci_conn_del+0x27e/0x6a0 net/bluetooth/hci_conn.c:611
 hci_phy_link_complete_evt.isra.0+0x5a4/0x7a0 net/bluetooth/hci_event.c:4677
 hci_event_packet+0x1973/0x858f net/bluetooth/hci_event.c:5898
 hci_rx_work+0x46b/0xa90 net/bluetooth/hci_core.c:4359
 process_one_work+0x864/0x1570 kernel/workqueue.c:2155
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
 kthread+0x30b/0x410 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

The buggy address belongs to the object at ffff8880a1256200
 which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 16 bytes inside of
 4096-byte region [ffff8880a1256200, ffff8880a1257200)
The buggy address belongs to the page:
page:ffffea0002849580 count:1 mapcount:0 mapping:ffff88812c39cdc0 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea0002930e88 ffffea0002224188 ffff88812c39cdc0
raw: 0000000000000000 ffff8880a1256200 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a1256100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a1256180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a1256200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8880a1256280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a1256300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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