==================================================================
BUG: KASAN: use-after-free in hci_chan_del+0x1c5/0x200 net/bluetooth/hci_conn.c:1753
Read of size 8 at addr ffff8880135b6118 by task syz-executor.0/8192

CPU: 0 PID: 8192 Comm: syz-executor.0 Not tainted 5.11.0-rc5-next-20210129-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+0x107/0x163 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:1753
 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:1485 [inline]
 hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1582
 hci_dev_do_close+0x569/0x1110 net/bluetooth/hci_core.c:1778
 hci_dev_close+0x14d/0x190 net/bluetooth/hci_core.c:1859
 hci_sock_ioctl+0x57d/0x840 net/bluetooth/hci_sock.c:1030
 sock_do_ioctl+0xcb/0x2d0 net/socket.c:1039
 sock_ioctl+0x477/0x6a0 net/socket.c:1179
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45e219
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f84eec64c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045e219
RDX: 0000000000000000 RSI: 00000000400448ca RDI: 0000000000000004
RBP: 000000000119bfc0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000119bf8c
R13: 00007ffc70fbffaf R14: 00007f84eec659c0 R15: 000000000119bf8c

Allocated by task 4844:
 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:403 [inline]
 ____kasan_kmalloc mm/kasan/common.c:434 [inline]
 ____kasan_kmalloc.constprop.0+0xa0/0xd0 mm/kasan/common.c:406
 kmalloc include/linux/slab.h:556 [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+0x44/0xa9

Freed by task 4844:
 kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38
 kasan_set_track+0x1c/0x30 mm/kasan/common.c:46
 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:357
 ____kasan_slab_free.part.0+0xe1/0x110 mm/kasan/common.c:364
 kasan_slab_free include/linux/kasan.h:191 [inline]
 slab_free_hook mm/slub.c:1562 [inline]
 slab_free_freelist_hook+0x82/0x1d0 mm/slub.c:1600
 slab_free mm/slub.c:3161 [inline]
 kfree+0xe5/0x7b0 mm/slub.c:4202
 kernfs_fop_release+0xe3/0x190 fs/kernfs/file.c:760
 __fput+0x283/0x920 fs/file_table.c:280
 task_work_run+0xdd/0x190 kernel/task_work.c:140
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x19/0x50 kernel/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880135b6100
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff8880135b6100, ffff8880135b6180)
The buggy address belongs to the page:
page:00000000e9b3337b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x135b6
flags: 0xfff00000000200(slab)
raw: 00fff00000000200 ffffea0000485a80 0000000600000006 ffff88800fc418c0
raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880135b6000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880135b6080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880135b6100: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880135b6180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880135b6200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================