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authorCornelia Huck <cornelia.huck@de.ibm.com>2012-11-08 23:24:12 -0500
committerRusty Russell <rusty@rustcorp.com.au>2012-11-08 23:24:24 -0500
commit237242bddc99041e15a4ca51b8439657cadaff17 (patch)
treea506fe81ea564d15ed2544d5bb477bc58405603f
parentf6a79af8f3701b5a0df431a76adee212616154dc (diff)
virtio: Don't access index after unregister.
Virtio wants to release used indices after the corresponding virtio device has been unregistered. However, virtio does not hold an extra reference, giving up its last reference with device_unregister(), making accessing dev->index afterwards invalid. I actually saw problems when testing my (not-yet-merged) virtio-ccw code: - device_add virtio-net,id=xxx -> creates device virtio<n> with n>0 - device_del xxx -> deletes virtio<n>, but calls ida_simple_remove with an index of 0 - device_add virtio-net,id=xxx -> tries to add virtio0, which is still in use... So let's save the index we want to release before calling device_unregister(). Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com> Acked-by: Sjur Brændeland <sjur.brandeland@stericsson.com> Cc: stable@kernel.org Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
-rw-r--r--drivers/virtio/virtio.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 1e8659ca27ef..809b0de59c09 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -225,8 +225,10 @@ EXPORT_SYMBOL_GPL(register_virtio_device);
225 225
226void unregister_virtio_device(struct virtio_device *dev) 226void unregister_virtio_device(struct virtio_device *dev)
227{ 227{
228 int index = dev->index; /* save for after device release */
229
228 device_unregister(&dev->dev); 230 device_unregister(&dev->dev);
229 ida_simple_remove(&virtio_index_ida, dev->index); 231 ida_simple_remove(&virtio_index_ida, index);
230} 232}
231EXPORT_SYMBOL_GPL(unregister_virtio_device); 233EXPORT_SYMBOL_GPL(unregister_virtio_device);
232 234