pool: free list modified: pipepl

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c037b5701899 Oops, commited wrong version of CLEANFILES in..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=15421d04180000
kernel config: https://syzkaller.appspot.com/x/.config?x=1bc15e68cd2a49e5
dashboard link: https://syzkaller.appspot.com/bug?extid=fa5320e0bae06cbcfd2d

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/318f9f2ca38f/disk-c037b570.raw.xz
bsd.gdb: https://storage.googleapis.com/syzbot-assets/48b274978922/bsd-c037b570.gdb.xz
kernel image: https://storage.googleapis.com/syzbot-assets/10df6380856b/kernel-c037b570.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+fa5320...@syzkaller.appspotmail.com

panic: pool_p_free: pipepl free list modified: page 0xfffffd806023d000; item addr 0xfffffd806023dee0; offset 0x0=0x0
Starting stack trace...
panic(ffffffff828ca0ce) at panic+0x159 sys/kern/subr_prf.c:229
pool_p_free(ffffffff82d16000,fffffd806270c318) at pool_p_free+0x1d3
pool_gc_pages(0) at pool_gc_pages+0x215 sys/kern/subr_pool.c:1583
taskq_thread(ffffffff82d04920) at taskq_thread+0x9b sys/kern/kern_task.c:450
end trace frame: 0x0, count: 253
End of stack trace.
syncing disks...25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 25 giving up

dump to dev 4,1 not possible
rebooting...
SeaBIOS (version 1.8.2-google)
Total RAM Size = 0x0000000080000000 = 2048 MiB
CPUs found: 2 Max CPUs supported: 2
SeaBIOS (version 1.8.2-google)
Machine UUID 860ebdd0-427f-2be6-5726-fd56b385017a
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 0x000f28a0: PCHS=0/0/0 translation=lba LCHS=520/128/63 s=4194304
Sending Seabios boot VM event.
Booting from Hard Disk 0...
>> OpenBSD/amd64 BOOT 3.65
boot> show all pools
boot: illegal argument all
boot> machine ddbcpu 0
machine: syntax error
boot> trace
boot> machine ddbcpu 1
machine: syntax error
boot> trace


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