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BUG: KASAN: use-after-free in hci_chan_del+0x1c5/0x200 net/bluetooth/hci_conn.c:1769
Read of size 8 at addr ffff88801770b418 by task syz-executor.4/16058

CPU: 0 PID: 16058 Comm: syz-executor.4 Not tainted 5.12.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:79 [inline]
 dump_stack+0x141/0x1d7 lib/dump_stack.c:120
 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232
 __kasan_report mm/kasan/report.c:399 [inline]
 kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416
 hci_chan_del+0x1c5/0x200 net/bluetooth/hci_conn.c:1769
 l2cap_conn_del+0x478/0x7b0 net/bluetooth/l2cap_core.c:1906
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:8168 [inline]
 l2cap_disconn_cfm+0x98/0xd0 net/bluetooth/l2cap_core.c:8161
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1486 [inline]
 hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1598
 hci_dev_do_close+0x569/0x1110 net/bluetooth/hci_core.c:1778
 hci_unregister_dev+0x263/0x1130 net/bluetooth/hci_core.c:3989
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x288/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x1a0 kernel/task_work.c:140
 exit_task_work include/linux/task_work.h:30 [inline]
 do_exit+0xbfc/0x2a60 kernel/exit.c:825
 do_group_exit+0x125/0x310 kernel/exit.c:922
 __do_sys_exit_group kernel/exit.c:933 [inline]
 __se_sys_exit_group kernel/exit.c:931 [inline]
 __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:931
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x465f69
Code: Unable to access opcode bytes at RIP 0x465f3f.
RSP: 002b:00007fff5db87ff8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000064 RCX: 0000000000465f69
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 00000000004bebcc R08: 000000000000000c R09: 0000000002e233bc
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000016
R13: 00007fff5db892d0 R14: 0000000002e233bc R15: 00007fff5db8a3e0

Allocated by task 18026:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:427 [inline]
 ____kasan_kmalloc mm/kasan/common.c:506 [inline]
 ____kasan_kmalloc mm/kasan/common.c:465 [inline]
 __kasan_kmalloc+0x99/0xc0 mm/kasan/common.c:515
 kmalloc include/linux/slab.h:554 [inline]
 kernfs_get_open_node fs/kernfs/file.c:552 [inline]
 kernfs_fop_open+0x957/0xd40 fs/kernfs/file.c:698
 do_dentry_open+0x4b9/0x11b0 fs/open.c:826
 do_open fs/namei.c:3365 [inline]
 path_openat+0x1c0e/0x27e0 fs/namei.c:3498
 do_filp_open+0x17e/0x3c0 fs/namei.c:3525
 do_sys_openat2+0x16d/0x420 fs/open.c:1187
 do_sys_open fs/open.c:1203 [inline]
 __do_sys_open fs/open.c:1211 [inline]
 __se_sys_open fs/open.c:1207 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1207
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Last potentially related work creation:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_record_aux_stack+0xe5/0x110 mm/kasan/generic.c:345
 __call_rcu kernel/rcu/tree.c:3039 [inline]
 call_rcu+0xb1/0x740 kernel/rcu/tree.c:3114
 inet_free_ifa net/ipv4/devinet.c:231 [inline]
 inetdev_destroy net/ipv4/devinet.c:319 [inline]
 inetdev_event+0x699/0x15c0 net/ipv4/devinet.c:1598
 notifier_call_chain+0xb5/0x200 kernel/notifier.c:83
 call_netdevice_notifiers_info+0xb5/0x130 net/core/dev.c:2063
 call_netdevice_notifiers_extack net/core/dev.c:2075 [inline]
 call_netdevice_notifiers net/core/dev.c:2089 [inline]
 unregister_netdevice_many+0x942/0x1760 net/core/dev.c:10905
 ip_tunnel_delete_nets+0x3eb/0x5b0 net/ipv4/ip_tunnel.c:1114
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:178
 cleanup_net+0x4ea/0xb10 net/core/net_namespace.c:595
 process_one_work+0x98d/0x1600 kernel/workqueue.c:2275
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2421
 kthread+0x3b1/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

The buggy address belongs to the object at ffff88801770b400
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff88801770b400, ffff88801770b480)
The buggy address belongs to the page:
page:00000000b79c9508 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff88801770b900 pfn:0x1770b
flags: 0xfff00000000200(slab)
raw: 00fff00000000200 ffffea0000995b88 ffffea000091ad08 ffff8880104418c0
raw: ffff88801770b900 000000000010000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88801770b300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
 ffff88801770b380: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88801770b400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff88801770b480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801770b500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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