kern/55493: panic in radixtree

[prlw1%cam.ac.uk@localhost]

>Number:         55493
>Category:       kern
>Synopsis:       panic in radixtree
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jul 16 11:35:00 +0000 2020
>Originator:     Patrick Welche
>Release:        NetBSD-9.99.69/amd64
>Organization:
>Environment:
>Description:
panic: kernel diagnostic assertion "*vpp == NULL" failed: file "/usr/src/local/netbsd/src/sys/lib/libkern/../../../common/lib/libc/gen/radixtree.c", line 591

A core file is available:

crash> bt
_KERNEL_OPT_NJOY_EAP() at 0
?() at ffffad54ce539298
sys_reboot() at sys_reboot
vpanic() at vpanic+0x15b
__x86_indirect_thunk_rax() at __x86_indirect_thunk_rax
radix_tree_insert_node() at radix_tree_insert_node+0x141
uvm_pagealloc_strat() at uvm_pagealloc_strat+0x55e
uao_get() at uao_get+0x524
ubc_fault() at ubc_fault+0x425
uvm_fault_internal() at uvm_fault_internal+0xc41
trap() at trap+0x501
--- trap (number 6) ---
copyout() at copyout+0x33
uiomove() at uiomove+0x84
ubc_uiomove() at ubc_uiomove+0x165
tmpfs_read() at tmpfs_read+0xbe
VOP_READ() at VOP_READ+0x40
vn_read() at vn_read+0x88
dofileread() at dofileread+0x79
sys_pread() at sys_pread+0xa0
syscall() at syscall+0x283
--- syscall (number 173) ---
syscall+0x283:

>How-To-Repeat:
Thanks to msaitoh's efforts in
http://mail-index.netbsd.org/current-users/2020/06/27/msg038985.html
I can now boot a LOCKDEBUG kernel.

To try to find the underlying issue of PR kern/55362 (dd to raidframe
fine, dump to raidframe fine (apparently, might be luck), dump to cgd
on raidframe not fine with differences on the platters - full dmesg over there) I was running dd zero to each of the raid disks simultaneously and doing a pbulk run. Just found the box had panicked and rebooted.
>Fix: