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BUG: KASAN: use-after-free in hci_chan_del+0x14f/0x190 net/bluetooth/hci_conn.c:1707
Read of size 8 at addr ffff8880a8498018 by task syz-executor.3/10514

CPU: 1 PID: 10514 Comm: syz-executor.3 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:1707
 l2cap_conn_del+0x61b/0x9e0 net/bluetooth/l2cap_core.c:1900
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:8159 [inline]
 l2cap_disconn_cfm+0x85/0xa0 net/bluetooth/l2cap_core.c:8152
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1355 [inline]
 hci_conn_hash_flush+0x114/0x220 net/bluetooth/hci_conn.c:1536
 hci_dev_do_close+0x5c6/0x1080 net/bluetooth/hci_core.c:1761
 hci_unregister_dev+0x1a3/0xe20 net/bluetooth/hci_core.c:3606
 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+0xb72/0x2a40 kernel/exit.c:805
 do_group_exit+0x125/0x310 kernel/exit.c:903
 get_signal+0x40b/0x1ee0 kernel/signal.c:2743
 do_signal+0x82/0x2520 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop arch/x86/entry/common.c:235 [inline]
 __prepare_exit_to_usermode+0x156/0x1f0 arch/x86/entry/common.c:269
 do_syscall_64+0x6c/0xe0 arch/x86/entry/common.c:393
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cce9
Code: Bad RIP value.
RSP: 002b:00007f3626fafcf8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 000000000078bf08 RCX: 000000000045cce9
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 000000000078bf08
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000078bf0c
R13: 00007ffc6e0b9f9f R14: 00007f3626fb09c0 R15: 000000000078bf0c

Allocated by task 30875:
 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
 __do_kmalloc mm/slab.c:3656 [inline]
 __kmalloc+0x17a/0x340 mm/slab.c:3665
 kmalloc include/linux/slab.h:560 [inline]
 copy_verifier_state+0x80d/0xa90 kernel/bpf/verifier.c:852
 is_state_visited kernel/bpf/verifier.c:8528 [inline]
 do_check kernel/bpf/verifier.c:8647 [inline]
 do_check_common+0x1445/0xc2d0 kernel/bpf/verifier.c:10479
 do_check_main kernel/bpf/verifier.c:10545 [inline]
 bpf_check+0x8448/0xcdc2 kernel/bpf/verifier.c:10997
 bpf_prog_load+0xdaf/0x1b50 kernel/bpf/syscall.c:2194
 __do_sys_bpf+0x1edf/0x4b10 kernel/bpf/syscall.c:4117
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 30875:
 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
 clear_jmp_history kernel/bpf/verifier.c:805 [inline]
 free_verifier_state+0x133/0x210 kernel/bpf/verifier.c:819
 is_state_visited kernel/bpf/verifier.c:8481 [inline]
 do_check kernel/bpf/verifier.c:8647 [inline]
 do_check_common+0x2968/0xc2d0 kernel/bpf/verifier.c:10479
 do_check_main kernel/bpf/verifier.c:10545 [inline]
 bpf_check+0x8448/0xcdc2 kernel/bpf/verifier.c:10997
 bpf_prog_load+0xdaf/0x1b50 kernel/bpf/syscall.c:2194
 __do_sys_bpf+0x1edf/0x4b10 kernel/bpf/syscall.c:4117
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a8498000
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff8880a8498000, ffff8880a8498080)
The buggy address belongs to the page:
page:ffffea0002a12600 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a8498200
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000278c048 ffffea0002675888 ffff8880aa000700
raw: ffff8880a8498200 ffff8880a8498000 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a8497f00: fb fb fb fb fb fb fb fb fc fc fc fc fb fb fb fb
 ffff8880a8497f80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a8498000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880a8498080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a8498100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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