linux-kernel - [PATCH repost] virtio: don't crash when device is buggy

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Message-ID: <20120916094427.GA24075@redhat.com>
Date:	Sun, 16 Sep 2012 12:44:27 +0300
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	Sjur Brændeland <sjurbren@...il.com>,
	Amit Shah <amit.shah@...hat.com>, linux-kernel@...r.kernel.org,
	Ohad Ben-Cohen <ohad@...ery.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	virtualization@...ts.linux-foundation.org
Subject: [PATCH repost] virtio: don't crash when device is buggy


Because of a sanity check in virtio_dev_remove, a buggy device can crash
kernel.  And in case of rproc it's userspace so it's not a good idea.
We are unloading a driver so how bad can it be?
Be less aggressive in handling this error: if it's a driver bug,
warning once should be enough.

Signed-off-by: Michael S. Tsirkin <mst@...hat.com>

--

3.6 material?

diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index c3b3f7f..1e8659c 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -159,7 +159,7 @@ static int virtio_dev_remove(struct device *_d)
 	drv->remove(dev);
 
 	/* Driver should have reset device. */
-	BUG_ON(dev->config->get_status(dev));
+	WARN_ON_ONCE(dev->config->get_status(dev));
 
 	/* Acknowledge the device's existence again. */
 	add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);

-- 
MST
--
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