kern/56436: panic from scsibus scan

[kim%netbsd.org@localhost (Kimmo Suominen)]

>Number:         56436
>Category:       kern
>Synopsis:       panic from scsibus scan
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Oct 02 19:45:00 +0000 2021
>Originator:     kim%netbsd.org@localhost (Kimmo Suominen)
>Release:        NetBSD 9.99.89 (202109271928Z)
>Organization:
>Environment:
System: NetBSD rendez-vous.gw.fi 9.99.89 NetBSD 9.99.89 (GENERIC.202109271928Z~GW) #1: Mon Sep 27 23:08:29 EEST 2021 kim%equinoxe.x.gw.fi@localhost:/p/netbsd/work/HEAD/amd64/obj/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:

	System panics from initiating a scsibus scan:
	# scsisctl /dev/scsibus0 scan 0 3

	[ 304916.143145] panic: kernel diagnostic assertion "KERNEL_LOCKED_P()" failed: file "/p/netbsd/cvs/src/sys/kern/subr_autoconf.c", line 1053
	[ 304916.143145] cpu1: Begin traceback...
	[ 304916.143145] vpanic() at netbsd:vpanic+0x156
	[ 304916.153145] __x86_indirect_thunk_rax() at netbsd:__x86_indirect_thunk_rax
	[ 304916.153145] config_match() at netbsd:config_match+0x85
	[ 304916.153145] mapply() at netbsd:mapply+0x26
	[ 304916.153145] config_search_internal() at netbsd:config_search_internal+0x16e
	[ 304916.153145] config_search() at netbsd:config_search+0x7d
	[ 304916.153145] scsi_probe_bus() at netbsd:scsi_probe_bus+0x4be
	[ 304916.153145] VOP_IOCTL() at netbsd:VOP_IOCTL+0x47
	[ 304916.153145] vn_ioctl() at netbsd:vn_ioctl+0xad
	[ 304916.153145] sys_ioctl() at netbsd:sys_ioctl+0x56d
	[ 304916.153145] syscall() at netbsd:syscall+0x196
	[ 304916.163146] --- syscall (number 54) ---
	[ 304916.163146] netbsd:syscall+0x196:
	[ 304916.163146] cpu1: End traceback...
	[ 304916.163146] dumping to dev 168,2 (offset=8, size=4192952):
	[ 304916.163146] dump failed: insufficient space (3407872 < 4895219)
	[ 304916.933141] rebooting...

>How-To-Repeat:

	I had added a new SCSI disk to the virtual machine and wanted
	the kernel to find it, so I ran

	# scsisctl /dev/scsibus0 scan 0 3

>Fix: