On 29/04/21(Thu) 12:07, Alexander Bluhm wrote:
> On Thu, Apr 29, 2021 at 11:08:30AM +0200, Mark Kettenis wrote:
> > > > panic: kernel diagnostic assertion "pg->wire_count == 0" failed: file
> > > > "/usr/src/sys/uvm/uvm_page.c", line 1265
> >
> > I suspect pmapae.c rev 1.61 causes this issue. Does reverting that
> > commit "fix" the issue?
> >
> > It won't really fix the issue as you may still hit the "can't locate PD
> > page"
> > panic.
>
> I think this diff prevents the panic. But I need one more test run
> to be sure.
This 4 pages pdir is never freed, so ok with me to revert this chunk if
it is the cause of the panic you see.
> One of my i386 machines triggers it during every make build, the
> other one is stable.
>
> wire count is 1
>
> struct vm_page at 0xd4fd3404 (76 bytes) {pageq = {tqe_next = (struct vm_page
> *)0xffffffff, tqe_prev = 0xffffffff}, objt = {rbt_parent = (struct rb_entry
> *)0xd267d084, rbt_left = (struct rb_entry *)0xd286028c, rbt_right = (struct
> rb_entry *)0xd4fd33c0, rbt_color = 0x0}, uanon = (struct vm_anon *)0x0,
> uobject = (struct uvm_object *)0xd0e58d0c, offset = 0x2552c000, pg_flags =
> 0x3200004, pg_version = 0x1, wire_count = 0x1, phys_addr = 0xcfd1e000, fpgsz
> = 0x0, mdpage = {pv_mtx = {mtx_owner = (volatile void *)0x0, mtx_wantipl =
> 0x90, mtx_oldipl = 0x90}, pv_list = (struct pv_entry *)0x0}}
>
> bluhm
>
> Index: arch/i386/i386/pmapae.c
> ===================================================================
> RCS file: /mount/openbsd/cvs/src/sys/arch/i386/i386/pmapae.c,v
> retrieving revision 1.61
> diff -u -p -r1.61 pmapae.c
> --- arch/i386/i386/pmapae.c 24 Apr 2021 09:44:45 -0000 1.61
> +++ arch/i386/i386/pmapae.c 28 Apr 2021 19:30:13 -0000
> @@ -1938,20 +1938,7 @@ pmap_enter_special_pae(vaddr_t va, paddr
> __func__, va);
>
> if (!pmap->pm_pdir_intel) {
> -#if notyet
> - /*
> - * XXX mapping is established via pmap_kenter() and lost
> - * after enabling PAE.
> - */
> - vapd = (vaddr_t)km_alloc(4 * NBPG, &kv_any, &kp_zero,
> - &kd_waitok);
> -#else
> - vapd = (vaddr_t)km_alloc(4 * NBPG, &kv_any, &kp_pageable,
> - &kd_waitok);
> - if (vapd != 0)
> - bzero((void *)vapd, 4 * NBPG);
> -#endif
> - if (vapd == 0)
> + if ((vapd = uvm_km_zalloc(kernel_map, 4 * NBPG)) == 0)
> panic("%s: kernel_map out of virtual space!", __func__);
> pmap->pm_pdir_intel = vapd;
> if (!pmap_extract(pmap, (vaddr_t)&pmap->pm_pdidx_intel,
>
