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BUG: KASAN: use-after-free in hci_send_acl+0xad6/0xc70 net/bluetooth/hci_core.c:3652
Read of size 8 at addr ffff88809f8e8798 by task kworker/u5:2/6507

CPU: 0 PID: 6507 Comm: kworker/u5:2 Not tainted 4.19.136-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci0 hci_rx_work
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_send_acl+0xad6/0xc70 net/bluetooth/hci_core.c:3652
 l2cap_send_cmd+0x1bd/0x210 net/bluetooth/l2cap_core.c:874
 l2cap_send_move_chan_cfm_icid net/bluetooth/l2cap_core.c:4655 [inline]
 l2cap_move_fail net/bluetooth/l2cap_core.c:5140 [inline]
 l2cap_move_channel_rsp net/bluetooth/l2cap_core.c:5179 [inline]
 l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5458 [inline]
 l2cap_sig_channel net/bluetooth/l2cap_core.c:5793 [inline]
 l2cap_recv_frame+0x6aa8/0xa550 net/bluetooth/l2cap_core.c:7017
 l2cap_recv_acldata+0x80e/0x910 net/bluetooth/l2cap_core.c:7588
 hci_acldata_packet net/bluetooth/hci_core.c:4178 [inline]
 hci_rx_work+0x455/0xa90 net/bluetooth/hci_core.c:4364
 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

Allocated by task 1226:
 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_chan_create+0x8e/0x310 net/bluetooth/hci_conn.c:1651
 l2cap_conn_add.part.0+0x18/0xc40 net/bluetooth/l2cap_core.c:7056
 l2cap_conn_add net/bluetooth/l2cap_core.c:7415 [inline]
 l2cap_connect_cfm+0x236/0xe70 net/bluetooth/l2cap_core.c:7373
 hci_connect_cfm include/net/bluetooth/hci_core.h:1246 [inline]
 hci_remote_features_evt net/bluetooth/hci_event.c:3017 [inline]
 hci_event_packet+0x3a31/0x858f net/bluetooth/hci_event.c:5779
 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

Freed by task 6507:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 hci_disconn_loglink_complete_evt net/bluetooth/hci_event.c:4755 [inline]
 hci_event_packet+0xf52/0x858f net/bluetooth/hci_event.c:5906
 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 ffff88809f8e8780
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff88809f8e8780, ffff88809f8e8800)
The buggy address belongs to the page:
page:ffffea00027e3a00 count:1 mapcount:0 mapping:ffff88812c39c640 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea0002806bc8 ffffea00027ed848 ffff88812c39c640
raw: 0000000000000000 ffff88809f8e8000 0000000100000015 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f8e8680: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff88809f8e8700: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff88809f8e8780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88809f8e8800: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff88809f8e8880: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
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