[ 300.3598033] panic: kernel diagnostic assertion "mutex_owned(pipe->pipe_lock)" failed: file "/syzkaller/managers/netbsd/kernel/sys/kern/sys_pipe.c", line 371 
[ 300.3698202] cpu1: Begin traceback...
[ 300.3798433] vpanic() at netbsd:vpanic+0x214
[ 300.3898543] _GLOBAL__sub_D_65535_0_cpu_configure() at netbsd:_GLOBAL__sub_D_65535_0_cpu_configure
[ 300.3998732] pipelock() at netbsd:pipelock+0xb0
[ 300.4199075] pipe_write() at netbsd:pipe_write+0x99
[ 300.4299228] dofilewrite() at netbsd:dofilewrite+0x1b7
[ 300.4399421] sys_write() at netbsd:sys_write+0x78
[ 300.4499586] sys___syscall() at netbsd:sys___syscall+0xe2
[ 300.4599786] syscall() at netbsd:syscall+0x348
[ 300.4699960] --- syscall (number 198) ---
[ 300.4699960] 6fd14623f4aa:
[ 300.4699960] cpu1: End traceback...

[ 300.4800102] dumping to dev 4,1 (offset=0, size=0): not possible
[ 300.4800102] rebooting...
SeaBIOS (version 1.8.2-20190322_093631-google)
Total RAM Size = 0x00000001e0000000 = 7680 MiB
CPUs found: 2     Max CPUs supported: 2
found virtio-scsi at 0:3
virtio-scsi vendor='Google' product='PersistentDisk' rev='1' type=0 removable=0
virtio-scsi blksize=512 sectors=4194304 = 2048 MiB
drive 0x000f29c0: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Booting from Hard Disk 0...

>> NetBSD/x86 BIOS Boot, Revision 5.10 (Tue Jul 17 14:59:51 UTC 2018) (from NetBSD 8.0)
>> Memory: 639/3144640 k

     1. Boot normally
     2. Boot single user
     3. Disable ACPI
     4. Disable ACPI and SMP
     5. Drop to boot prompt