From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sasha Levin <sasha.levin@oracle.com>
Subject: Re: [PATCH 2/2] kvmtool: assume dead vcpus are paused too
Date: Wed, 4 Nov 2015 18:51:12 -0500
Message-ID: <563A99F0.10100@oracle.com>
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Cc: andre.przywara@arm.com, josh@joshtriplett.org, penberg@kernel.org,
	asias.hejun@gmail.com, kvm@vger.kernel.org
To: Will Deacon <will.deacon@arm.com>
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On 11/04/2015 06:51 AM, Will Deacon wrote:
> +	mutex_lock(&pause_lock);
> +
> +	/* The kvm->cpus array contains a null pointer in the last location */
> +	for (i = 0; ; i++) {
> +		if (kvm->cpus[i])
> +			pthread_kill(kvm->cpus[i]->thread, SIGKVMEXIT);
> +		else
> +			break;
> +	}
> +
> +	kvm__continue(kvm);

In this scenario: if we grabbed pause_lock, signaled vcpu0 to exit, and it did
before we called kvm__continue(), we won't end up releasing pause_lock, which
might cause a lockup later, no?


Thanks,
Sasha