re: 10.0 crashes on leaving X

interesting.  the panic only happens on the sun4m becuase the
sun4c version of this function continues instead of panicking.

---
void
pmap_protect4_4c(struct pmap *pm, vaddr_t sva, vaddr_t eva, vm_prot_t prot)
...
        for (va = sva; va < eva;) {
...
                if (rp->rg_nsegmap == 0) {
                        va = nva;
                        continue;
--- vs ---
pmap_page_protect4m(struct vm_page *pg, vm_prot_t prot)
...
        while (pv != NULL) {
...
                rp = &pm->pm_regmap[vr];
                if (rp->rg_nsegmap == 0)
                        panic("pmap_remove_all: empty vreg");
---

i wonder if there is some race condition happening.  don't
worry, we believe you're seeing this :)


.mrg.