linux-kernel

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [day] [month] [year] [list]

Message-ID: <20111207102507.GB8326@redhat.com>
Date:	Wed, 7 Dec 2011 12:25:08 +0200
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Amit Shah <amit.shah@...hat.com>
Cc:	Virtualization List <virtualization@...ts.linux-foundation.org>,
	Rusty Russell <rusty@...tcorp.com.au>, levinsasha928@...il.com,
	linux-kernel@...r.kernel.org

Pavel Machek <pavel@....cz>,
"Rafael J. Wysocki" <rjw@...k.pl>,
Len Brown <len.brown@...el.com>,
linux-pm@...r.kernel.org
Bcc: 
Subject: Re: [PATCH v4 12/12] virtio: balloon: Add freeze, restore handlers
 to support S4
Reply-To: 
In-Reply-To: <5deccc36afa59032f0e3b10a653773bad511f303.1323199985.git.amit.shah@...hat.com>

On Wed, Dec 07, 2011 at 01:18:50AM +0530, Amit Shah wrote:
> Now to not race with a host issuing ballooning requests while we are in
> the process of freezing, we just exit from the vballoon kthread when the
> processes are asked to freeze.  Upon thaw and restore, we re-start the
> thread.

...

> ---
>  drivers/virtio/virtio_balloon.c |   79 ++++++++++++++++++++++++++++++++++++++-
>  1 files changed, 78 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 8bf99be..10ec638 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -258,7 +258,13 @@ static int balloon(void *_vballoon)
>  	while (!kthread_should_stop()) {
>  		s64 diff;
>  
> -		try_to_freeze();
> +		/*
> +		 * On suspend, we want to exit this thread.  We will
> +		 * start a new thread on resume.
> +		 */
> +		if (freezing(current))
> +			break;
> +
>  		wait_event_interruptible(vb->config_change,
>  					 (diff = towards_target(vb)) != 0
>  					 || vb->need_stats_update

...

Note: this relies on kthreads being frozen before devices.
Looking at kernel/power/hibernate.c this is the case,
but I think we should add a comment to note this.

Also Cc linux-pm crowd in case I got it wrong.

-- 
MST
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/