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From: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <250b3fa9-6321-e1b1-35e5-c7fdaa6ef6d7@redhat.com>
Date: Thu, 5 Jul 2018 14:01:42 +0200
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Subject: Re: [Qemu-devel] [PATCH] exec.c: check RAMBlock validity before
 changing its flag
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To: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= <clg@kaod.org>, Peter Xu <peterx@redhat.com>
Cc: qemu-devel@nongnu.org, "Dr . David Alan Gilbert" <dgilbert@redhat.com>, Peter Maydell <peter.maydell@linaro.org>, "Michael S. Tsirkin" <mst@redhat.com>, Alex Williamson <alex.williamson@redhat.com>, David Gibson <david@gibson.dropbear.id.au>

On 05/07/2018 07:56, C=C3=A9dric Le Goater wrote:
> Hello Paolo,
>=20
> On 07/04/2018 02:16 PM, Paolo Bonzini wrote:
>> On 04/07/2018 11:55, Peter Xu wrote:
>>>>     commit b0e56e0b63f350691b52d3e75e89bb64143fbeff
>>>>     Author: Hu Tao <hutao@cn.fujitsu.com>
>>>>     Date:   Wed Apr 2 15:13:27 2014 +0800
>>>>
>>>>     unset RAMBlock idstr when unregister MemoryRegion
>>>>
>>>>     Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
>>>>     Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>>>>
>>>> whose commit message is a bit lacking, but
>>>> http://lists.gnu.org/archive/html/qemu-devel/2014-04/msg00282.html h=
elps
>>>> more.  It seems like the original bug was a reference count issue.
>>>>
>>>> Clearing the new migratable flag should also be unnecessary.
>>> But even if we get rid of vmstate_unregister_ram(), the leak could
>>> still be there?
>>>
>>> I'm not sure what was leaked when b0e56e0b6 was introduced, I feel
>>> like it's the RAMBlock of the memdev.  Here I think the ROM memory
>>> region seems to be leaked as well (along with the RAMBlock inside)?
>>
>> The leak would be another bug that vmstate_unregister_ram is just
>> papering over.  We need to test memory unplug with
>> vmstate_unregister_ram removed, and fix bugs if any.
>=20
> So for the time being, you would just get rid of pci_del_option_rom()
> which only does vmstate_unregister_ram() ?=20

Yes, I think so.

Paolo