Re: kern/58118: NetBSD/i386 Xen PV guest panic "fpudna from userland"

[Brad Spencer <brad%anduin.eldar.org@localhost>]

The following reply was made to PR kern/58118; it has been noted by GNATS.

From: Brad Spencer <brad%anduin.eldar.org@localhost>
To: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
Cc: gnats-bugs%netbsd.org@localhost, kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/58118: NetBSD/i386 Xen PV guest panic "fpudna from userland"
Date: Fri, 05 Apr 2024 18:47:38 -0400

 Manuel Bouyer <bouyer%antioche.eu.org@localhost> writes:
 
 > On Fri, Apr 05, 2024 at 05:30:01PM +0000, brad%anduin.eldar.org@localhost wrote:
 >> >Number:         58118
 >> >Category:       kern
 >> >Synopsis:       NetBSD/i386 Xen PV guest panic "fpudna from userland"
 >
 > FWIW I've seen this from time to time running anita tests:
 > http://largo.lip6.fr/~bouyer/NetBSD-tests/xen/
 >
 > I'm seeing FPU issues for PVH and HVM guests too, and for both i386 and amd64.
 >
 > This happens since the lazy FPU context switching has been removed.
 >
 > I tried to track it down but failed. The issue may be in Xen itself.
 >
 > I just upgraded the test box to Xen 4.18, maybe this will help ...
 
 
 I also noticed this on the DOM0:
 
 (XEN) d354v0 Triple fault - invoking HVM shutdown action 1
 (XEN) *** Dumping Dom354 vcpu#0 state: ***
 (XEN) ----[ Xen-4.15.3nb0  x86_64  debug=n  Not tainted ]----
 (XEN) CPU:    6
 (XEN) RIP:    0008:[<ffffffff80235384>]
 (XEN) RFLAGS: 0000000000010046   CONTEXT: hvm guest (d354v0)
 (XEN) rax: 0000000000000000   rbx: 0000000000000000   rcx: 0000000000000000
 (XEN) rdx: ffffd36a5495a780   rsi: 0000000000000002   rdi: ffff9a0000002000
 (XEN) rbp: ffff9a0240900e50   rsp: ffff9a0240900e50   r8:  0000000020000020
 (XEN) r9:  0070e9311f5676db   r10: 000000001dcd6500   r11: 0000000000000000
 (XEN) r12: 0000000000000000   r13: 0000000000000000   r14: ffff9a0240900fb0
 (XEN) r15: ffffffff81887ae0   cr0: 000000008005003b   cr4: 00000000003606b0
 (XEN) cr3: 0000000113b07000   cr2: 00007f7fffa88fe8
 (XEN) fsb: 00007402ee324850   gsb: ffffffff8183bd40   gss: 0000000000000000
 (XEN) ds: 0023   es: 0023   fs: 0000   gs: 0000   ss: 0010   cs: 0008
 
 
 I can't say with 100% confidence that domain 354 was the NetBSD/i386
 that panic'ed, but it is possible.  I have made node of the domain id
 number and will see if it survives the cron job run.  The build it was
 doing completed without a panic...  but I could probably start it all
 over again and see if I can force the issue to happen.
 
 
 
 -- 
 Brad Spencer - brad%anduin.eldar.org@localhost - KC8VKS - http://anduin.eldar.org