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BUG: KASAN: use-after-free in hci_chan_del+0x1c5/0x200 net/bluetooth/hci_conn.c:1728
Read of size 8 at addr ffff888011045e18 by task syz-executor.0/12204

CPU: 0 PID: 12204 Comm: syz-executor.0 Not tainted 5.10.0-rc4-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+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x4c8 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 hci_chan_del+0x1c5/0x200 net/bluetooth/hci_conn.c:1728
 l2cap_conn_del+0x478/0x7b0 net/bluetooth/l2cap_core.c:1900
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:8161 [inline]
 l2cap_disconn_cfm+0x98/0xd0 net/bluetooth/l2cap_core.c:8154
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1441 [inline]
 hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1557
 hci_dev_do_close+0x569/0x1110 net/bluetooth/hci_core.c:1770
 hci_unregister_dev+0x223/0xfe0 net/bluetooth/hci_core.c:3827
 vhci_release+0x70/0xe0 drivers/bluetooth/hci_vhci.c:340
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:151
 exit_task_work include/linux/task_work.h:30 [inline]
 do_exit+0xb64/0x29b0 kernel/exit.c:809
 do_group_exit+0x125/0x310 kernel/exit.c:906
 get_signal+0x428/0x1f00 kernel/signal.c:2758
 arch_do_signal+0x82/0x2390 arch/x86/kernel/signal.c:811
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0x100/0x1a0 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x38/0x260 kernel/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: Unable to access opcode bytes at RIP 0x45de8f.
RSP: 002b:00007f91ebc23cf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000118bf28 RCX: 000000000045deb9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000118bf28
RBP: 000000000118bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffdd933f5df R14: 00007f91ebc249c0 R15: 000000000118bf2c

Allocated by task 4902:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc.constprop.0+0xc2/0xd0 mm/kasan/common.c:461
 kmalloc include/linux/slab.h:552 [inline]
 kernfs_get_open_node fs/kernfs/file.c:571 [inline]
 kernfs_fop_open+0x957/0xd40 fs/kernfs/file.c:717
 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
 do_open fs/namei.c:3252 [inline]
 path_openat+0x1b9a/0x2730 fs/namei.c:3369
 do_filp_open+0x17e/0x3c0 fs/namei.c:3396
 do_sys_openat2+0x16d/0x420 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0x119/0x1c0 fs/open.c:1188
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 4902:
 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+0x102/0x140 mm/kasan/common.c:422
 slab_free_hook mm/slub.c:1544 [inline]
 slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1577
 slab_free mm/slub.c:3142 [inline]
 kfree+0xdb/0x360 mm/slub.c:4124
 kernfs_fop_release+0xe3/0x190 fs/kernfs/file.c:779
 __fput+0x285/0x920 fs/file_table.c:281
 task_work_run+0xdd/0x190 kernel/task_work.c:151
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:164 [inline]
 exit_to_user_mode_prepare+0x17e/0x1a0 kernel/entry/common.c:191
 syscall_exit_to_user_mode+0x38/0x260 kernel/entry/common.c:266
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff888011045e00
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff888011045e00, ffff888011045e80)
The buggy address belongs to the page:
page:00000000ac7d6bed refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11045
flags: 0xfff00000000200(slab)
raw: 00fff00000000200 ffffea00008bb480 0000000500000002 ffff888010041640
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888011045d00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888011045d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888011045e00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff888011045e80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888011045f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
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