[Qemu-devel] Re: 64-bit Qemu and remote GDB to Kernel Error

[Jan Kiszka]

Am 04.10.2010 04:47, Matt Davis wrote:
> Hello,
> I am trying to debug a 32-bit linux kernel with gdb and qemu.  My qemu
> runs the 64-bit kernel as:
> address@hidden> qemu -kernel vmlinuz -S -s  (not using kvm).  If I try with
> kvm the breakpoint does not even seem to get tripped.

Which qemu version is affected by this issue?

> 
> And then I fire up gdb on my 64-bit machine (the same one running
> qemu).  And I set my "target remote :1234" and set a breakpoint.
> Anyways, I seem to catch my breakpoint, but when it should be tripping
> I get the following error :
> Remote 'g' packet reply is too long: <data>
> 
> I have done similar stuff fine on a 32bit machine running both 32-bit
> qemu and a 32-bit kernel.  I have also googled, and this seems to not
> be uncommon (circa 2008).  But I have not seen anything recently
> regarding this.  Should it be working now?  If not is there a better
> solution?  I tried, on my 64bit machine, to run a 32-bit kernel in
> qemu, but my breakpoints were still not tripping in gdb.  Yes, the
> kernel did have debugging flags built in.  I also forced the gdb
> architecture to use "set arch i386:x86-64" not much difference if I
> recall.
> 
> The following thread had similar issues when trying to set a break in
> 64 bit land, but not mention of the error I reported above.  These
> possibly cold be related:
> http://lists.gnu.org/archive/html/qemu-devel/2008-05/msg00287.html

Please also see this thread
http://thread.gmane.org/gmane.comp.emulators.qemu/80327. Did you follow
the procedure I suggested? I cannot derive this from your description.

Jan

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