Re: port-xen/58561 (panic: kernel diagnostic assertion, "x86_read_psl() == 0" failed: file, "/home/netbsd/10/src/sys/arch/x86/x86/pmap.c", line 3581)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Jan 12, 2026 at 11:20:34PM +0100, Manuel Bouyer wrote:
> On Sun, Jan 11, 2026 at 08:35:10PM -0800, Konrad Schroder wrote:
> > On 1/10/2026 2:33 PM, Manuel Bouyer wrote:
> > > And this assembly work may have allowed me to find the problem.
> > > Basically, the CLI and STI macros are not atomic on Xen PV, and if preemption
> > > happens at a bad time we may end up updating the upcall_mask of our previous
> > > CPU. The attached patch should close this race condition; hopefully it's
> > > the last one.
> > 
> > I can confirm that, at least in my case, this allows me to build
> > continuously all day without a crash.
> 
> Good, it points that we're on the right track.
> Can you try the attached patch instead ? It tries to limit the extra
> instructions to only places where it's needed, and add DIAGNOSTIC code
> to check it's really not needed in other places.

Sorry this patch has a bug; working on an updated version
stay tuned.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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