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On Mon, May 26, 2025 at 12:04:59AM +0200, Mark Kettenis wrote:
> > Date: Sun, 25 May 2025 23:20:46 +0200
> > From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
> >
> > On Thu, May 22, 2025 at 08:19:38PM +0200, Mark Kettenis wrote:
> > > > Date: Thu, 22 May 2025 18:54:08 +0200
> > > > From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
> > [...]
> > > > *Bzzzt*
> > > >
> > > > The same LDOM was busy compiling two devel/llvm copies under dpb(1).
> > > > Input welcome, I'm not sure yet what other ddb commands could help.
> > > >
> > > > login: panic: trap type 0x34 (mem address not aligned): pc=1012f68 npc=1012f6c pstate=820006<PRIV,IE>
> > > > Stopped at db_enter+0x8: nop
> > > > TID PID UID PRFLAGS PFLAGS CPU COMMAND
> > > > 57488 1522 0 0x11 0 1 perl
> > > > 435923 9891 55 0x1000002 0 4 cc1plus
> > > > 135860 36368 55 0x1000002 0 13 cc1plus
> > > > 333743 96489 55 0x1000002 0 0 cc1plus
> > > > 433162 55422 55 0x1000002 0 9 cc1plus
> > > > 171658 49723 55 0x1000002 0 5 cc1plus
> > > > 47127 57536 55 0x1000002 0 10 cc1plus
> > > > 56600 9350 55 0x1000002 0 14 cc1plus
> > > > 159792 13842 55 0x1000002 0 6 cc1plus
> > > > 510019 10312 55 0x1000002 0 8 cc1plus
> > > > 20489 65709 55 0x1000002 0 15 cc1plus
> > > > 337455 42430 55 0x1000002 0 12 cc1plus
> > > > 401407 80906 55 0x1000002 0 11 cc1plus
> > > > 22993 62317 55 0x1000002 0 2 cc1plus
> > > > 114916 17058 55 0x1000002 0 7 cc1plus
> > > > *435412 33034 0 0x14000 0x200 3K pagedaemon
> > > > trap(400fe6b19b0, 34, 1012f68, 820006, 3, 42) at trap+0x334
> > > > Lslowtrap_reenter(40015a58a00, 77b5db2000, deadbeefdeadc0c7, 1d8, 2df0fc468, 468) at Lslowtrap_reenter+0xf8
> > > > pmap_page_protect(40010716ab8, c16, 1cc9860, 193dfa0, 1cc9000, 1cc9000) at pmap_page_protect+0x1fc
> > > > uvm_pagedeactivate(40010716a50, 40015a50d24, 18667a0, 0, 0, 1c8dac0) at uvm_pagedeactivate+0x54
> > > > uvmpd_scan_active(0, 0, 270f2, 18667a0, 0, ffffffffffffffff) at uvmpd_scan_active+0x150
> > > > uvm_pageout(400fe6b1e08, 55555556, 18667a0, 1c83f08, 1c83000, 1c8dc18) at uvm_pageout+0x2dc
> > > > proc_trampoline(0, 0, 0, 0, 0, 0) at proc_trampoline+0x10
> > > > https://www.openbsd.org/ddb.html describes the minimum info required in bug
> > > > reports. Insufficient info makes it difficult to find and fix bugs.
> > >
> > > If there are pmap issues, pmap_page_protect() is certainly the first
> > > place I'd look. I'll start looking, but don't expect to have much
> > > time until after monday.
> >
> > Indeed this crash lies in pmap_page_protect(). llvm-objdump -dlS says
> > it's stopped at l.2499:
> >
> > } else {
> > pv_entry_t firstpv;
> > /* remove mappings */
> >
> > firstpv = pa_to_pvh(pa);
> > mtx_enter(&pg->mdpage.pvmtx);
> >
> > /* First remove the entire list of continuation pv's*/
> > while ((pv = firstpv->pv_next) != NULL) {
> > --> data = pseg_get(pv->pv_pmap, pv->pv_va & PV_VAMASK);
> >
> > /* Save REF/MOD info */
> > firstpv->pv_va |= pmap_tte2flags(data);
> >
> > ; /sys/arch/sparc64/sparc64/pmap.c:2499
> > ; data = pseg_get(pv->pv_pmap, pv->pv_va & PV_VAMASK);
> > 3c10: a7 29 30 0d sllx %g4, 13, %l3
> > 3c14: d2 5c 60 10 ldx [%l1+16], %o1
> > 3c18: d0 5c 60 08 ldx [%l1+8], %o0
> > --> 3c1c: 40 00 00 00 call 0
> > 3c20: 92 0a 40 13 and %o1, %l3, %o1
> >
> > As discussed with miod I suspect the crash actually lies inside
> > pseg_get(), but I can't prove it.
>
> Can you try the diff below. I've nuked pmap_collect() on other
> architectures since it is hard to make "mpsafe". The current sparc64
> certainly isn't.
>
> If this fixes the crashes, I can see if it is possible to make it
> "mpsafe" on sparc64.
I see. Indeed this function stood out when I looked at the file. Can
I really just empty it out like this, or should I also drop
__HAVE_PMAP_COLLECT?
Yesterday the machine crashed again in a nearby place in
pmap_page_protect().
login: pmap_page_protect: gotten pseg empty!
Stopped at pmap_page_protect+0x620: nop
ddb{4}> tr
uvm_pagedeactivate(4000d1510a0, 19d2ce0, 193edd0, 40015a507e4, 1, 1) at uvm_pagedeactivate+0x54
uvn_flush(401053a3310, 0, 11c8000, 14, 1, 0) at uvn_flush+0x448
uvn_detach(401053a3310, 40101633630, 1, 0, 0, 1000000) at uvn_detach+0x158
uvm_unmap_detach(400fe6b5c68, 0, 9a7, 40015a507e4, 40015a507e4, 18f7828) at uvm_unmap_detach+0x68
uvm_map_teardown(400130912e0, 4000, 1939240, 4010599c000, 54d, 17b2ff8) at uvm_map_teardown+0x184
uvmspace_free(1cd7000, 400130912e0, 4, 17b2ff8, 0, 6) at uvmspace_free+0x64
reaper(40015a507e0, 40015a507e0, db, 100, 1c04038, 4000) at reaper+0x100
proc_trampoline(0, 0, 0, 0, 0, 0) at proc_trampoline+0x10
ddb{4}>
This time it's pmap.c l.2534:
/* Then remove the primary pv */
if (pv->pv_pmap != NULL) {
data = pseg_get(pv->pv_pmap, pv->pv_va & PV_VAMASK);
/* Save REF/MOD info */
pv->pv_va |= pmap_tte2flags(data);
if (pseg_set(pv->pv_pmap, pv->pv_va & PV_VAMASK, 0, 0)) {
printf("pmap_page_protect: gotten pseg empty!\n");
--> db_enter();
/* panic? */
}
It's not the first crash with uvmspace_free() going through
uvm_pagedeactivate(), so I agree with you that a fix is probably
needed for mpi's uvm_purge() diff (which I haven't tested yet on that
box).
--
jca