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BUG: KASAN: use-after-free in hci_send_acl+0xabe/0xc60 net/bluetooth/hci_core.c:4174
Read of size 8 at addr ffff8880a733bd18 by task kworker/u5:0/1545

CPU: 1 PID: 1545 Comm: kworker/u5:0 Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: hci3 hci_rx_work
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x198/0x1fd 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
 hci_send_acl+0xabe/0xc60 net/bluetooth/hci_core.c:4174
 l2cap_send_cmd+0x6d5/0x8a0 net/bluetooth/l2cap_core.c:949
 l2cap_send_move_chan_cfm_icid net/bluetooth/l2cap_core.c:4916 [inline]
 l2cap_move_fail net/bluetooth/l2cap_core.c:5400 [inline]
 l2cap_move_channel_rsp net/bluetooth/l2cap_core.c:5439 [inline]
 l2cap_bredr_sig_cmd net/bluetooth/l2cap_core.c:5718 [inline]
 l2cap_sig_channel net/bluetooth/l2cap_core.c:6417 [inline]
 l2cap_recv_frame+0x6936/0xae10 net/bluetooth/l2cap_core.c:7659
 l2cap_recv_acldata+0x7f6/0x8e0 net/bluetooth/l2cap_core.c:8314
 hci_acldata_packet net/bluetooth/hci_core.c:4703 [inline]
 hci_rx_work+0x4c7/0xb50 net/bluetooth/hci_core.c:4894
 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

Allocated by task 6985:
 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+0x174/0x2c0 mm/slab.c:3554
 kmalloc include/linux/slab.h:554 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 hci_chan_create+0x9b/0x330 net/bluetooth/hci_conn.c:1713
 l2cap_conn_add.part.0+0x1e/0xe10 net/bluetooth/l2cap_core.c:7698
 l2cap_conn_add net/bluetooth/l2cap_core.c:8140 [inline]
 l2cap_connect_cfm+0x23b/0x1090 net/bluetooth/l2cap_core.c:8098
 hci_connect_cfm include/net/bluetooth/hci_core.h:1423 [inline]
 hci_remote_features_evt net/bluetooth/hci_event.c:3222 [inline]
 hci_event_packet+0x36e2/0x87a8 net/bluetooth/hci_event.c:6086
 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

Freed by task 1545:
 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:3422 [inline]
 kfree+0x10e/0x2b0 mm/slab.c:3760
 hci_disconn_loglink_complete_evt net/bluetooth/hci_event.c:5018 [inline]
 hci_event_packet+0x3e33/0x87a8 net/bluetooth/hci_event.c:6213
 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 ffff8880a733bd00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff8880a733bd00, ffff8880a733bd80)
The buggy address belongs to the page:
page:00000000d3daa2e0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xa733b
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027e4888 ffffea00027715c8 ffff8880aa040400
raw: 0000000000000000 ffff8880a733b000 0000000100000010 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a733bc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc
 ffff8880a733bc80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a733bd00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880a733bd80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a733be00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
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