kern/57485: panic: lock error: Reader / writer lock: rw_vector_exit,466: assertion failed: RW_COUNT(rw) != 0: lock

[campbell+netbsd%mumble.net@localhost]

>Number:         57485
>Category:       kern
>Synopsis:       panic: lock error: Reader / writer lock: rw_vector_exit,466: assertion failed: RW_COUNT(rw) != 0: lock
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jun 24 13:45:00 +0000 2023
>Originator:     Taylor R Campbell
>Release:        netbsd-10
>Organization:
The NetBSD Spawndation
>Environment:
NetBSD nanocons.local 10.0_BETA NetBSD 10.0_BETA (GENERIC64) #3: Tue Jan 17 16:42:00 UTC 2023  root@manticore.local:/usr/obj/10/evbarm64/sys/arch/evbarm/compile/GENERIC64 evbarm
>Description:
[ 7074949.954133] Reader / writer lock error: rw_vector_exit,466: assertion failed: RW_COUNT(rw) != 0

[ 7074949.964130] lock address : netbsd:exec_lock
[ 7074949.964130] current cpu  :                  3
[ 7074949.974129] current lwp  : 0xffff00007c5cf580
[ 7074949.974129] UVM: pid 26536 (sh), uid 0 killed: out of swap
[ 7074949.984130] owner/count  : 000000000000000000 flags    : 000000000000000000

[ 7074949.984130] panic: lock error: Reader / writer lock: rw_vector_exit,466: assertion failed: RW_COUNT(rw) != 0: lock 0xffffc000011e9400 cpu 3 lwp 0xffff00007c5cf580
[ 7074950.004128] cpu3: Begin traceback...
[ 7074950.004128] trace fp ffffc000af6b7c00
[ 7074950.014129] fp ffffc000af6b7c30 vpanic() at ffffc00000585c58 netbsd:vpanic+0x178
[ 7074950.024135] fp ffffc000af6b7c90 panic() at ffffc00000585d64 netbsd:panic+0x44
[ 7074950.034134] fp ffffc000af6b7d20 lockdebug_abort() at ffffc0000057a7ac netbsd:lockdebug_abort+0xdc
[ 7074950.044134] fp ffffc000af6b7de0 rw_exit() at ffffc0000054368c netbsd:rw_exit+0x88
[ 7074950.064144] fp ffffc000af6b7e30 spawn_return() at ffffc0000051ec4c netbsd:spawn_return+0x59c
[ 7074950.074143] tf ffffc000af6b7ed0 el0_trap() at ffffc000000b6ff0 netbsd:el1_trap_exit+0x68
[ 7074950.084140] ---- SVC Instruction Execution: trapframe 0xffffc000af6b7ed0 (304 bytes) ----
[ 7074950.094136]     pc=0000f40bc7243a08,   spsr=0000000060000000
[ 7074950.094136]    esr=00000000560001da,    far=0000f560f4dfa8e0
[ 7074950.104136]     x0=0000ffffffc9545c,     x1=000000000113a550
[ 7074950.114135]     x2=0000000000000000,     x3=0000ffffffc95470
[ 7074950.114135]     x4=0000ffffffc95510,     x5=0000f40bc713e780
[ 7074950.124135]     x6=0000000000000000,     x7=0000000000000000
[ 7074950.124135]     x8=0000000000000000,     x9=0000000000000006
[ 7074950.134139]    x10=0000000000000040,    x11=000000000000003f
[ 7074950.144136]    x12=0000000000001230,    x13=000003ffffff2d16
[ 7074950.144136]    x14=8f5c28f5c28f5c29,    x15=0000ffffffcb4588
[ 7074950.154135]    x16=000000000115e2a8,    x17=0000f40bc7243a04
[ 7074950.154135]    x18=00000000000007e7,    x19=0000ffffffc95510
[ 7074950.164135]    x20=0000f40bc713e780,    x21=0000ffffffc95460
[ 7074950.174135]    x22=0000000000000001,    x23=000000000113a778
[ 7074950.174135]    x24=0000ffffffc95470,    x25=0000000000000001
[ 7074950.184136]    x26=0000000000000001,    x27=0000000000000016
[ 7074950.184136]    x28=0000ffffffcb5858, fp=x29=0000ffffffc953f0
[ 7074950.194134] lr=x30=0000000001113de0,     sp=0000ffffffc953f0
[ 7074950.204134] ------------------------------------------------
[ 7074950.204134] cpu3: End traceback...

[ 7074950.214135] dump to dev 92,1 not possible
[ 7074955.214251] rebooting...

dmesg was previously dominated by oom-killer messages.  (No swap on this machine, and mdnsd appears to have a memory leak which makes the oom-killer regularly kill daily activities.)
>How-To-Repeat:
unknown
>Fix:
Yes, please!