Subject: Re: NetBSD crashes on 4 GB Supermicro
To: None <firstname.lastname@example.org>
From: Manuel Bouyer <email@example.com>
Date: 05/03/2007 19:44:21
On Thu, May 03, 2007 at 12:18:02PM -0400, firstname.lastname@example.org wrote:
> I'm having a problem running a NetBSD domU on one particular type of
> SuperMicro PDSMI+ motherboard
> 4 GB RAM (about 3.5 MB usable)
> Xen 3.0.3-0 (non-PAE, of course)
> dom0: Linux 126.96.36.199
> Normally NetBSD will crash immediately upon startup on these systems.
> Linux domUs work just fine. NetBSD also works fine on other 4GB systems.
> The only way I can get NetBSD to work on these is if I tell Xen to
> limit the RAM usage to 3G or less on the command line (mem=3072m).
> That last 512MB or so may not seem like much, but without PAE support,
> I'm trying to make use of every last available MB.
I've seen the same issue on a Dell 2950 system. From memory, linux
domU couldn't start either, but this system isn't running Xen now so
I can't check.
> I have no idea how to debug a domU. Any help would be appreciated.
> This is what Xen has to say about it:
> (XEN) domain_crash_sync called from entry.S (ff150e49)
> (XEN) Domain 1 (vcpu#0) crashed on cpu#1:
> (XEN) ----[ Xen-3.0.3-0 x86_32 debug=n Not tainted ]----
> (XEN) CPU: 1
> (XEN) EIP: e019:[<c02b6ea9>]
> (XEN) EFLAGS: 00000246 CONTEXT: guest
> (XEN) eax: ffffffff ebx: d097d003 ecx: d097d000 edx: 00000000
> (XEN) esi: 0000005b edi: c0455000 ebp: c0317bb4 esp: c0317b78
> (XEN) cr0: 8005003b cr4: 000026d0 cr3: d097c000 cr2: 00000000
> (XEN) ds: e021 es: e021 fs: 0000 gs: 0000 ss: e021 cs: e019
> (XEN) Guest stack trace from esp=c0317b78:
> (XEN) 00000000 c02b6ea9 0001e019 00010046 c02b798c d097a154 d0973061 00000000
> (XEN) 00000000 00000000 c0454000 00000005 c0450c10 c0450000 c0459000 00000000
> (XEN) c0100179 c0317bbc 0000e021 c01044bc c0104520 00000000 00000000 00000000
> (XEN) 00000000 00000000 00000000 c02ec8a0 00000000 00000000 00000000 00000000
> (XEN) 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
> [many more lines of zeros]
build a XEN3_DOMU kernel with -g and boot it. Then use gdb netbsd.gdb
to match the eip value (c02b6ea9 here) to function/line in the source
code. It's quite possible that this will be in assembly code;
then you can use 'disass' to find the instruction.
You can also try to walk the stack dump to reconstruct the function
Manuel Bouyer <email@example.com>
NetBSD: 26 ans d'experience feront toujours la difference