Commit ff6f66f6 authored Oct 02, 2015 by Cathy Avery Committed by Sasha Levin Nov 15, 2015

xen-blkfront: check for null drvdata in blkback_changed (XenbusStateClosing)



[ Upstream commit a54c8f0f2d7df525ff997e2afe71866a1a013064 ]

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 <cathy.avery@oracle.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

parent 0b3fefd2

drivers/block/xen-blkfront.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1911,6 +1911,7 @@ static void blkback_changed(struct xenbus_device *dev,
		break;
		/* Missed the backend's Closing state -- fallthrough */
		case XenbusStateClosing:
		if (info)
		blkfront_closing(info);
		break;
		}