From a54c8f0f2d7df525ff997e2afe71866a1a013064 Mon Sep 17 00:00:00 2001 From: Cathy Avery Date: Fri, 2 Oct 2015 09:35:01 -0400 Subject: [PATCH] xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing) xen-blkfront will crash if the check to talk_to_blkback() in blkback_changed()(XenbusStateInitWait) returns an error. The driver data is freed and info is set to NULL. Later during the close process via talk_to_blkback's call to xenbus_dev_fatal() the null pointer is passed to and dereference in blkfront_closing. CC: stable@vger.kernel.org Signed-off-by: Cathy Avery Signed-off-by: Konrad Rzeszutek Wilk --- drivers/block/xen-blkfront.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index 6d89ed35d80c..c8fdbc77f9b1 100644 --- a/drivers/block/xen-blkfront.c +++ b/drivers/block/xen-blkfront.c @@ -1968,7 +1968,8 @@ static void blkback_changed(struct xenbus_device *dev, break; /* Missed the backend's Closing state -- fallthrough */ case XenbusStateClosing: - blkfront_closing(info); + if (info) + blkfront_closing(info); break; } }