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BUG: KASAN: use-after-free in hci_chan_del+0x14f/0x190 net/bluetooth/hci_conn.c:1728
Read of size 8 at addr ffff88809de67218 by task syz-executor284/6848

CPU: 1 PID: 6848 Comm: syz-executor284 Not tainted 5.8.0-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/0x436 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 hci_chan_del+0x14f/0x190 net/bluetooth/hci_conn.c:1728
 l2cap_conn_del+0x61b/0x9e0 net/bluetooth/l2cap_core.c:1900
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:8160 [inline]
 l2cap_disconn_cfm+0x85/0xa0 net/bluetooth/l2cap_core.c:8153
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1438 [inline]
 hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1557
 hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1770
 hci_unregister_dev+0x1bd/0xe30 net/bluetooth/hci_core.c:3790
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x33c/0x880 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_sys_exit kernel/exit.c:872 [inline]
 __se_sys_exit kernel/exit.c:870 [inline]
 __x64_sys_exit+0x3e/0x50 kernel/exit.c:870
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x402bfe
Code: Bad RIP value.
RSP: 002b:00007f759d1e6de0 EFLAGS: 00000246 ORIG_RAX: 000000000000003c
RAX: ffffffffffffffda RBX: 00007f759d1e7700 RCX: 0000000000402bfe
RDX: 000000000000003c RSI: 00000000007fb000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 00000000000000f1 R09: 00007f759d1e7700
R10: 00007f759d1e79d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffd84c5b06f R14: 00007f759d1e79c0 R15: 0000000000000001

Allocated by task 6850:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:494
 kmem_cache_alloc_trace+0x14f/0x2d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [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]
 le_conn_complete_evt+0x1153/0x1740 net/bluetooth/hci_event.c:5190
 hci_le_conn_complete_evt net/bluetooth/hci_event.c:5215 [inline]
 hci_le_meta_evt+0x745/0x3ff0 net/bluetooth/hci_event.c:5915
 hci_event_packet+0x2e25/0x87a8 net/bluetooth/hci_event.c:6192
 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 6850:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf5/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x103/0x2c0 mm/slab.c:3757
 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 ffff88809de67200
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff88809de67200, ffff88809de67280)
The buggy address belongs to the page:
page:ffffea00027799c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88809de67900
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000273ff48 ffffea0002795848 ffff8880aa000700
raw: ffff88809de67900 ffff88809de67000 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88809de67100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88809de67180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88809de67200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88809de67280: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88809de67300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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