[Qemu-devel] Re: [PATCH] qemu: work around for "posix-aio-compat"

[Paolo Bonzini]

On 10/20/2009 08:39 PM, Mark McLoughlin wrote:
> On Thu, 2009-10-08 at 22:37 +0200, Michael S. Tsirkin wrote:
> > With commit ee3993069ff55fa6f1c64daf1e09963e340db8e4,
> > "posix-aio-compat: avoid signal race when spawning a thread"
> > winxp installation on a raw format file fails
> > during disk format, with a message "your
> > disk may be damaged".
> >
> > This commit moved signal mask from aio thread to creating thread.
> > It turns out if we keep the mask in aio thread as well, the problem
> > disappears. It should not be needed, but since this is harmless, let's
> > keep it around until someone inclined to debug pthread library internals
> > can check this issue.
> >
> > While we are at it, convert sigprocmask to pthread_sigmask
> > as per posix.
>
> FWIW, I just started hitting a boot hang with qemu.git and --enable-kvm
> on a Fedora 11 machine with a Fedora 11 guest.
>
> I bisected it back to malc's commit, found this thread, applied
> Michael's patch and confirmed that it fixes the problem for me too.

If anybody can send me the output of compiling the "strange" file with 
and without the patch, both with "-fdump-tree-all -fdump-rtl-all -O2 
--save-temps -g" flags, I could try debugging it in GCC.

It will be huge, so bz/gz/lzip it.

Paolo