EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
Buffer I/O error on dev loop4, logical block 1, lost sync page write
EXT4-fs (loop4): I/O error while writing superblock
Oops: general protection fault, probably for non-canonical address 0xdffffc000000000b: 0000 [#1] SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000058-0x000000000000005f]
CPU: 1 UID: 0 PID: 8536 Comm: syz.4.1034 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:klist_remove+0x156/0x340
Code: 4d 89 f5 49 c1 ed 03 43 80 7c 3d 00 00 74 08 4c 89 f7 e8 1d e3 91 f6 4d 8b 26 49 83 e4 fe 49 8d 7c 24 58 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 74 05 e8 fe e2 91 f6 49 8b 44 24 58 48 89 44 24 08
RSP: 0018:ffffc9000b317620 EFLAGS: 00010202
RAX: 000000000000000b RBX: ffff88810c128000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000058
RBP: ffffc9000b317720 R08: ffffffff90172403 R09: 1ffffffff202e480
R10: dffffc0000000000 R11: fffffbfff202e481 R12: 0000000000000000
R13: 1ffff1102e4cae0c R14: ffff888172657060 R15: dffffc0000000000
FS:  00007f3a163786c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b32220ff8 CR3: 00000001aaad0000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 device_move+0x193/0x730
 hci_conn_del_sysfs+0xb8/0x1a0
 hci_conn_del+0xc36/0x1230
 hci_conn_hash_flush+0x191/0x260
 hci_dev_close_sync+0x821/0x10e0
 hci_unregister_dev+0x21a/0x5a0
 vhci_release+0x152/0x1a0
 __fput+0x44f/0xa60
 task_work_run+0x1d9/0x270
 do_exit+0x70f/0x22c0
 do_group_exit+0x21b/0x2d0
 get_signal+0x1284/0x1330
 arch_do_signal_or_restart+0xbc/0x840
 exit_to_user_mode_loop+0x8c/0x4d0
 do_syscall_64+0x33e/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: ffff:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 002b:0000001000000000 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000001000000018
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:klist_remove+0x156/0x340
Code: 4d 89 f5 49 c1 ed 03 43 80 7c 3d 00 00 74 08 4c 89 f7 e8 1d e3 91 f6 4d 8b 26 49 83 e4 fe 49 8d 7c 24 58 48 89 f8 48 c1 e8 03 <42> 80 3c 38 00 74 05 e8 fe e2 91 f6 49 8b 44 24 58 48 89 44 24 08
RSP: 0018:ffffc9000b317620 EFLAGS: 00010202
RAX: 000000000000000b RBX: ffff88810c128000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000058
RBP: ffffc9000b317720 R08: ffffffff90172403 R09: 1ffffffff202e480
R10: dffffc0000000000 R11: fffffbfff202e481 R12: 0000000000000000
R13: 1ffff1102e4cae0c R14: ffff888172657060 R15: dffffc0000000000
FS:  00007f3a163786c0(0000) GS:ffff8882a928d000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555955b3950 CR3: 00000001aaad0000 CR4: 00000000000006f0
