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From: Rusty Russell <rusty@rustcorp.com.au>
To: Amit Shah <amit.shah@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org,
	"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH RFC] virtio_blk: fix config handler race
Date: Wed, 21 Dec 2011 11:03:31 +1030	[thread overview]
Message-ID: <877h1qdaqs.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20111207153901.GA23820@redhat.com>

On Wed, 7 Dec 2011 17:39:02 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> Fix a theoretical race related to config work
> handler: a config interrupt might happen
> after we flush config work but before we
> reset the device. It will then cause the
> config work to run during or after reset.

Thanks for the reminder.  Apologies that this slipped through :(

> As a solution
> 1. flush after reset when we know there will be no more interrupts
> 2. add a flag to disable config access before reset

It's crude, but it works.  Applied.

If this happens again, do we want a "__virtio_device_disable" which
stops any interrupts from being delivered?  That would make this neater,
though the implementation might be a bit nasty.

Thanks,
Rusty.

WARNING: multiple messages have this Message-ID (diff)
From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>, Amit Shah <amit.shah@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH RFC] virtio_blk: fix config handler race
Date: Wed, 21 Dec 2011 11:03:31 +1030	[thread overview]
Message-ID: <877h1qdaqs.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20111207153901.GA23820@redhat.com>

On Wed, 7 Dec 2011 17:39:02 +0200, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> Fix a theoretical race related to config work
> handler: a config interrupt might happen
> after we flush config work but before we
> reset the device. It will then cause the
> config work to run during or after reset.

Thanks for the reminder.  Apologies that this slipped through :(

> As a solution
> 1. flush after reset when we know there will be no more interrupts
> 2. add a flag to disable config access before reset

It's crude, but it works.  Applied.

If this happens again, do we want a "__virtio_device_disable" which
stops any interrupts from being delivered?  That would make this neater,
though the implementation might be a bit nasty.

Thanks,
Rusty.

  parent reply	other threads:[~2011-12-21  0:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-07 15:39 [PATCH RFC] virtio_blk: fix config handler race Michael S. Tsirkin
2011-12-07 15:39 ` Michael S. Tsirkin
2011-12-20 19:42 ` Michael S. Tsirkin
2011-12-20 19:42   ` Michael S. Tsirkin
2011-12-21  0:33 ` Rusty Russell [this message]
2011-12-21  0:33   ` Rusty Russell

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