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BUG: KASAN: use-after-free in hci_chan_del+0x1b4/0x1f0 net/bluetooth/hci_conn.c:1683
Read of size 8 at addr ffff8880b3b48498 by task syz-executor.1/21229

CPU: 0 PID: 21229 Comm: syz-executor.1 Not tainted 4.19.188-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+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load8_noabort+0x88/0x90 mm/kasan/report.c:433
 hci_chan_del+0x1b4/0x1f0 net/bluetooth/hci_conn.c:1683
 l2cap_conn_del+0x45e/0x6e0 net/bluetooth/l2cap_core.c:1739
 l2cap_disconn_cfm net/bluetooth/l2cap_core.c:7441 [inline]
 l2cap_disconn_cfm+0x98/0xd0 net/bluetooth/l2cap_core.c:7434
 hci_disconn_cfm include/net/bluetooth/hci_core.h:1261 [inline]
 hci_conn_hash_flush+0x127/0x260 net/bluetooth/hci_conn.c:1512
 hci_dev_do_close+0x659/0xf10 net/bluetooth/hci_core.c:1668
 hci_rfkill_set_block+0xe7/0x160 net/bluetooth/hci_core.c:2102
 rfkill_set_block+0x1f9/0x540 net/rfkill/core.c:353
 rfkill_fop_write+0x250/0x4a0 net/rfkill/core.c:1249
 __vfs_write+0xf7/0x770 fs/read_write.c:485
 vfs_write+0x1f3/0x540 fs/read_write.c:549
 ksys_write+0x12b/0x2a0 fs/read_write.c:599
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x466459
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f38ace58188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466459
RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 00000000004bf9fb R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf60
R13: 00007ffe050014bf R14: 00007f38ace58300 R15: 0000000000022000

Allocated by task 19930:
 kmem_cache_alloc_trace+0x12f/0x380 mm/slab.c:3625
 kmalloc include/linux/slab.h:515 [inline]
 sock_alloc_inode+0x5f/0x250 net/socket.c:247
 alloc_inode+0x5d/0x180 fs/inode.c:211
 new_inode_pseudo+0x14/0xe0 fs/inode.c:911
 sock_alloc+0x3c/0x260 net/socket.c:547
 __sock_create+0xba/0x740 net/socket.c:1240
 sock_create net/socket.c:1316 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1346
 __do_sys_socket net/socket.c:1355 [inline]
 __se_sys_socket net/socket.c:1353 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1353
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 18:
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xcc/0x210 mm/slab.c:3822
 __rcu_reclaim kernel/rcu/rcu.h:231 [inline]
 rcu_do_batch kernel/rcu/tree.c:2584 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2897 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2864 [inline]
 rcu_process_callbacks+0xa0d/0x18b0 kernel/rcu/tree.c:2881
 __do_softirq+0x265/0x980 kernel/softirq.c:292

The buggy address belongs to the object at ffff8880b3b48480
 which belongs to the cache kmalloc-128 of size 128
The buggy address is located 24 bytes inside of
 128-byte region [ffff8880b3b48480, ffff8880b3b48500)
The buggy address belongs to the page:
page:ffffea0002ced200 count:1 mapcount:0 mapping:ffff88813bff0640 index:0xffff8880b3b48a80
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffffea000283d5c8 ffffea00028343c8 ffff88813bff0640
raw: ffff8880b3b48a80 ffff8880b3b48000 0000000100000014 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b3b48380: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8880b3b48400: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
>ffff8880b3b48480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880b3b48500: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
 ffff8880b3b48580: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
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