I reported a reproducible failure of KASSERT on powerpc/booke in which
destination of pmap_copy_page(9) is executable:
https://mail-index.netbsd.org/port-powerpc/2016/09/11/msg003498.html
By adding the similar KASSERTs to mips kernel, I observed the same
failure on ERLITE (evbmips64-eb):
# uname -mpr
7.99.38 evbmips mips64eb
# cd /usr/pkgsrc/lang/perl5; make
(snip)
=> Checking for portability problems in extracted files
(snip)
Use which C compiler? [gcc]
execve_loadvm: check exec failed 8
execve_loadvm: check exec failed 8
execve_loadvm: check exec failed 8
execve_loadvm: check exec failed 8
Checking for GNU cc in disguise and/or its version number...
panic: kernel diagnostic assertion
"!VM_PAGEMD_EXECPAGE_P(VM_PAGE_TO_MD(dst_pg))" failed: file
"/var/build/src/sys/arch/mips/mips/pmap_machdep.c", line 628
kernel: breakpoint trap
Stopped in pid 2328.1 (sed) at netbsd:cpu_Debugger+0x4: jr ra
bdslot: nop