Bluetooth: hci0: ACL packet for unknown connection handle 200
Bluetooth: hci0: ACL packet for unknown connection handle 200
Bluetooth: hci0: ACL packet for unknown connection handle 200
==================================================================
BUG: KASAN: use-after-free in hci_send_acl+0xad6/0xc70 net/bluetooth/hci_core.c:3652
Read of size 8 at addr ffff88809f384f18 by task kworker/0:2/2928

CPU: 0 PID: 2928 Comm: kworker/0:2 Not tainted 4.19.136-syzkaller #0
Bluetooth: hci0: ACL packet for unknown connection handle 200
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events l2cap_info_timeout
Call Trace:
Bluetooth: hci0: ACL packet for unknown connection handle 200
 __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
Bluetooth: hci0: ACL packet for unknown connection handle 200
 hci_send_acl+0xad6/0xc70 net/bluetooth/hci_core.c:3652
Bluetooth: hci0: ACL packet for unknown connection handle 200
 l2cap_send_cmd+0x1bd/0x210 net/bluetooth/l2cap_core.c:874
 l2cap_conn_start+0x355/0x9d0 net/bluetooth/l2cap_core.c:1488
Bluetooth: hci0: ACL packet for unknown connection handle 200
Bluetooth: hci0: ACL packet for unknown connection handle 200
 process_one_work+0x864/0x1570 kernel/workqueue.c:2155
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
Bluetooth: hci0: ACL packet for unknown connection handle 200
 kthread+0x30b/0x410 kernel/kthread.c:246
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Bluetooth: hci0: ACL packet for unknown connection handle 200

Allocated by task 6500:
 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
Bluetooth: hci0: ACL packet for unknown connection handle 200
 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
Bluetooth: hci0: ACL packet for unknown connection handle 200
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Freed by task 6500:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 hci_chan_list_flush net/bluetooth/hci_conn.c:1691 [inline]
 hci_conn_cleanup+0xf0/0x590 net/bluetooth/hci_conn.c:121
 hci_conn_del+0x27e/0x6a0 net/bluetooth/hci_conn.c:611
Bluetooth: hci0: ACL packet for unknown connection handle 200
 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
Bluetooth: hci0: ACL packet for unknown connection handle 200

The buggy address belongs to the object at ffff88809f384f00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff88809f384f00, ffff88809f384f80)
The buggy address belongs to the page:
page:ffffea00027ce100 count:1 mapcount:0 mapping:ffff88812c39c640 index:0x0
flags: 0xfffe0000000100(slab)
raw: 00fffe0000000100 ffffea000248d588 ffffea00027bcf88 ffff88812c39c640
Bluetooth: hci0: ACL packet for unknown connection handle 200
raw: 0000000000000000 ffff88809f384000 0000000100000015 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809f384e00: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
Bluetooth: hci0: ACL packet for unknown connection handle 200
 ffff88809f384e80: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
Bluetooth: hci0: ACL packet for unknown connection handle 200
>ffff88809f384f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88809f384f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809f385000: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fb fb
==================================================================