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)

["Konrad Schroder via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR port-xen/58561; it has been noted by GNATS.

From: Konrad Schroder <perseant%hhhh.org@localhost>
To: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
Cc: gnats-bugs%NetBSD.org@localhost, port-xen-maintainer%netbsd.org@localhost,
 netbsd-bugs%netbsd.org@localhost, gnats-admin%netbsd.org@localhost, riastradh%NetBSD.org@localhost,
 campbell+netbsd%mumble.net@localhost, cherry%NetBSD.org@localhost
Subject: 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)
Date: Sun, 11 Jan 2026 20:35:10 -0800

 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.
 
 Thanks!
 
 Konrad Schroder
 perseant%hhhh.org@localhost