Messages in this thread | | | Date | Tue, 21 Oct 2008 01:22:41 +0200 | From | Ingo Molnar <> | Subject | Re: [Lguest] lguest: unhandled trap |
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* Rusty Russell <rusty@rustcorp.com.au> wrote:
> On Monday 20 October 2008 18:22:36 Ingo Molnar wrote: > > * Rusty Russell <rusty@rustcorp.com.au> wrote: > > > On Monday 20 October 2008 12:50:09 Tiago Maluta wrote: > > > > --- On Sun, 10/19/08, Rusty Russell <rusty@rustcorp.com.au> wrote: > > > > > > Hi, > > > > > > > > > > > > I'm using 2.6.27-05323-g26e9a39 and when I try to > > > > > > > > > > use lguest: > > > > > > ~#Documentation/lguest/lguest 128 vmlinux > > > > > > lguest: unhandled trap 14 at 0xc0594f6a (0xff900000) > > > > > > > > > > Yes, I found the same issue. Does this fix it for you? > > > > > > > > Yes. This code fixed the problem. > > > > > > Thanks. Ingo, can you push this? > > > > > > Subject: lguest: don't try DMI > > > > > > dmi_scan_machine breaks under lguest; this is the simplest fix (though > > > ugly). Perhaps this hurts Xen too? > > > > > > Error: > > > lguest: unhandled trap 14 at 0xc04edeae (0xffa00000) > > > > > > Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> > > > > > > diff -r 47449cd8e3d8 drivers/firmware/dmi_scan.c > > > --- a/drivers/firmware/dmi_scan.c Fri Oct 17 12:14:40 2008 +1100 > > > +++ b/drivers/firmware/dmi_scan.c Fri Oct 17 20:54:30 2008 +1100 > > > @@ -369,6 +369,11 @@ void __init dmi_scan_machine(void) > > > char __iomem *p, *q; > > > int rc; > > > > > > +#ifdef CONFIG_PARAVIRT > > > + if (strcmp(pv_info.name, "lguest") == 0) > > > + goto error; > > > +#endif > > > + > > > > hm, could you give some more background please? I'm not subscribed to > > the lguest list and the thread is not Cc:-ed to lkml (Cc:-ed it now). > > The patch looks quite ugly because it adds a special-case. > > > > Was the problem introduced by: > > > > 5649b7c: x86: add DMI quirk for AMI BIOS which corrupts address 0xc000 > > during > > > > perhaps? > > > > i think Xen can withstand DMI scanning just fine. > > > > without having seen any background, my general feeling is that lguest > > should either do what Xen does and reserve the classic BIOS ranges that > > we probe - or we should make DMI scanning more robust by making sure > > real RAM ranges are never probed. (only ranges that the BIOS itself > > marks as reserved in the e820 map) > > > > (with exceptions for the first 4K perhaps.) > > > > Ingo > > Yes, after this discussion I'm not even sure why it's triggering: even > if there's crap in the memory it should not fault. Digging further.
we could also add an x86_quirks entry to skip the particular DMI scan that is causing problems. Would be nice to avoid it though, and fix lguest if possible.
Ingo
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