Re: [Qemu-devel] [PATCH RFC 6/6] xen: Add backtrace for serious issues.

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Wed, Jul 01, 2015 at 02:06:30PM +0100, Stefano Stabellini wrote:
> On Mon, 29 Jun 2015, Konrad Rzeszutek Wilk wrote:
> > When debugging issues that caused the emulator to kill itself
> > or skipping certain operations (unable to write to host
> > registers) an stack trace will most definitly aid in debugging
> > the problem.
> > 
> > As such this patch uses the most basic backtrace to print out
> > details.
> > 
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> 
> I think it could be useful, but it cannot be done as a xen-hvm.c thing.
> It should be somewhere generic, maybe under util? Stefan, any
> suggestions?

Yes, it seems like a util/ thing.  backtrace() and
backtrace_symbols_fd() are glibc-specific so it must not break the build
on other platforms.

I think the reason we've surivived without backtraces so far is because
fatal errors are typically handled with abort(3).  It causes a core dump
so you have the full process state, including backtraces.

I'm fine with adding a backtrace function though since it's more
lightweight and allows for graceful shutdown or error recovery.

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