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Date: Tue, 16 May 2017 16:07:37 +0800
From: Fam Zheng <famz@redhat.com>
Message-ID: <20170516080737.GB27669@lemon.lan>
References: <20170516072414.19025-1-famz@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v2] virtio: Move memory_listener_unregister
 to .unrealize
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To: qemu-devel@nongnu.org
Cc: Paolo Bonzini <pbonzini@redhat.com>, Jason Wang <jasowang@redhat.com>, qemu-stable@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>

On Tue, 05/16 15:24, Fam Zheng wrote:
> The root cause of the crash is not obvious here, but the change
> regardlessly makes sense so it's proposed here: the listener was
> registered in .realize(), so do the cleanup in the matching .unrealize()
> rather than the .finalize() callback.

Actually it seem calling memory_listener_unregister in .instance_finalize is not
safe because it can be in the RCU thread.  This race is what caused the
corruption of the listener lists.

So I think this patch is doing the right thing.

Fam