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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <c9438426-1f1e-c6eb-9b90-79a6b62e537a@redhat.com>
Date: Mon, 12 Sep 2016 18:44:17 +0200
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Subject: [Qemu-devel] [s390] possible deadlock in handle_sigp?
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To: KVM list <kvm@vger.kernel.org>, Cornelia Huck <cornelia.huck@de.ibm.com>, Christian Borntraeger <borntraeger@de.ibm.com>, qemu-devel <qemu-devel@nongnu.org>

I think that two CPUs doing reciprocal SIGPs could in principle end up
waiting on each other to complete their run_on_cpu.  If the SIGP has to
be synchronous the fix is not trivial (you'd have to put the CPU in a
state similar to cpu->halted = 1), otherwise it's enough to replace
run_on_cpu with async_run_on_cpu.

Thanks,

Paolo