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RE: [Xen-devel] segfault in VM

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: RE: [Xen-devel] segfault in VM
From: James Harper <JamesH@xxxxxxxxxxxxxxxx>
Date: Tue, 20 Jul 2004 20:42:09 +1000
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Thread-topic: [Xen-devel] segfault in VM
I still get corruption with these latest patches. In this case I had started 2 domains and was pinging them both fairly hard, I didn't get as far as running it out of memory.

From: Keir Fraser
Sent: Tue 20/07/2004 5:59 PM
To: James Harper
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] segfault in VM

I've just checked in a few networking fixes that should make things
rather more robust in low-memory conditions. I suspect there are still
some bugs lurking somewhere, but hopefully this has thinned out the
bugs somewhat.

 -- Keir

> bk pull only showed 2 patches, neither of which affected kernels so
> I didn't bother recompiling.
> I have seen an error (shown by my diff script 'compare' or by xend
> doing silly things like crashing), by simply starting another domain
> and pinging it with something like:
> ping -s 1400 -i 0.001
> (ping -f might do it but I think it goes a bit fast)
> That occured once after about 5 minutes, but then not again for the 10 or so minutes I left it running.
> running it out of memory with this code:
> #include <stdio.h>
> #include <stdlib.h>
> int main() {
>         char *buf;
>         int mem = 0;
>         int size = 1;
>         char rnd;
>         rnd = rand() & 255;
>         while(1) {
>                 buf = (char *)malloc(size*1024*1024);
>                 memset(buf, rnd, size*1024*1024);
>                 if (buf != NULL) {
>                         mem += size;
>                         printf("%d\n", mem);
>                 }
>         }
> }
> causes a crash far more quickly. I guess it's possible that those are two different errors though...
> James