Re: [Qemu-devel] [PATCH] scripts/qemugdb: support coroutine backtrace in coredumps

[Simon Marchi <simark@simark.ca>]

On 2018-04-09 10:08 PM, Stefan Hajnoczi wrote:
> I wonder what the point of select-frame is then...
> 
> I have CCed the GDB mailing list.  Maybe someone can help us.  Context:
> 
> QEMU implements coroutines using jmpbuf.  We'd like to print coroutine
> call stacks in GDB and have a script that works when a process is being
> debugged (it sets the registers).
> 
> Now we'd like to extend the script to work on core dumps where it's not
> possible to set registers (since there is no process being debugged).
> 
> Is there a way to backtrace an arbitrary call stack in a core dump?

Not that I know of.  The "frame <stack-addr> <pc-addr>" form of the frame
command sounds like it should be usable to achieve that, but it doesn't
seem to work in that way.  I really wonder if it's working as it was
intended initially.  I guess using that form of the frame command should
override/mask the real current values of $sp and $pc?

Simon