assert failed: mutex_owned(pipe->pipe_lock)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 5eba7b0ad839 Fix typo in kcov.h
git tree: netbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=140dcee0c00000
dashboard link: https://syzkaller.appspot.com/bug?extid=d0eb5807031212c0cb6c

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+d0eb58...@syzkaller.appspotmail.com

login: [ 86.1458763] panic: kernel diagnostic
assertion "mutex_owned(pipe->pipe_lock)" failed:
file "/syzkaller/managers/netbsd/kernel/sys/kern/sys_pipe.c", line 371
[ 86.1608399] cpu0: Begin traceback...
[ 86.1608399] vpanic() at netbsd:vpanic+0x214
[ 86.1608399] _GLOBAL__sub_D_65535_0_cpu_configure() at
netbsd:_GLOBAL__sub_D_65535_0_cpu_configure
[ 86.1608399] pipelock() at netbsd:pipelock+0xb0
[ 86.1608399] pipe_write() at netbsd:pipe_write+0x99
[ 86.1608399] dofilewrite() at netbsd:dofilewrite+0x154
[ 86.1608399] sys_write() at netbsd:sys_write+0x78
[ 86.1608399] sys___syscall() at netbsd:sys___syscall+0xe2
[ 86.1608399] syscall() at netbsd:syscall+0x30e
[ 86.1608399] --- syscall (number 198) ---
[ 86.1608399] 76787763f4aa:
[ 86.1608399] cpu0: End traceback...

[ 86.1608399] dumping to dev 4,1 (offset=0, size=0): not possible
[ 86.1608399] rebooting...
SeaBIOS (version 1.8.2-20190204_181744-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 0x000f2a00: 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
| / - \ | / - 39065424\ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - +2877616\ | / - [1062170\ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / +1363032- \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / +1044688- \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ |
/ - \ | / - ]=0x2b4fc38
\ | / - \ | / - \ | / - \ | / - \ | / - \ | / - \ | / - WARNING: couldn't
open /var/db/entropy-file
WARNING: 1 module failed to load


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with
syzbot.

[Maxime Villard]

#syz fix: Clean up pipe structure before recycling it.