Re: [Qemu-devel] Stack corruption problem with SeaBIOS/gPXE under QEMU

[Kevin O'Connor]

On Mon, Nov 16, 2009 at 04:02:20PM +0200, Avi Kivity wrote:
>> Something that is likely related, I am seeing reboot failures in  
>> seabios's pmm_free.  Immediately after loading gpxe, seabios is in an  
>> endless loop there, likely due to memory corruption.
>>
>> This is with -smp 2, rebooting Fedora 9 after installation.
>
> With gpxe disabled, rebooting works as expected.
>
> Note the tests were performed with the stack at 64K to avoid triggering  
> the known issue.

Hi Avi,

Can you send the full qemu command line that you used?  I can't seem
to reproduce this on my setup.

I do see an issue if SeaBIOS's reboot vector is called (eg, by using
"sendkey ctrl-alt-delete" while still in the bios) because seabios
allows gpxe to modify itself, and on a seabios only reboot the gpxe
rom isn't recopied and gpxe therefore gets confused.  However, on a
linux invoked reboot, it looks like a full machine reset occurs and
qemu recopies the gpxe rom, so that doesn't seem to be an issue.

BTW, how did you change the stack location?  I've been changing
seabios by setting BUILD_STACK_ADDR to 0x7000 (or 0xfff0) in
src/config.h.

-Kevin