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Subject: Re: [Qemu-devel] [PATCH] qemu: work around for "posix-aio-compat"
From: Mark McLoughlin <markmc@redhat.com>
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Date: Tue, 20 Oct 2009 19:39:41 +0100
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org

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.

Cheers,
Mark.