From: aliguori <aliguori@c046a42c-6fe2-441c-8c8c-71466251a162>
Date: Sun, 29 Mar 2009 01:31:51 +0000 (+0000)
Subject: check for bs->drv in bdrv_flush (Christoph Hellwig)
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=081501daceca74d2091e798d5dcd342c14d66d1a;p=qemu.git

check for bs->drv in bdrv_flush (Christoph Hellwig)

All the bdrv_ helpers should check for bs->drv being zero as that means
there is no backend image open.  bdrv_flush fails to perform that check
and can thus cause NULL pointer dereferences.

Found using qemu-io.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6943 c046a42c-6fe2-441c-8c8c-71466251a162
---

diff --git a/block.c b/block.c
index a9523ed5b5..4da3bcba16 100644
--- a/block.c
+++ b/block.c
@@ -1002,6 +1002,8 @@ const char *bdrv_get_device_name(BlockDriverState *bs)
 
 void bdrv_flush(BlockDriverState *bs)
 {
+    if (!bs->drv)
+        return;
     if (bs->drv->bdrv_flush)
         bs->drv->bdrv_flush(bs);
     if (bs->backing_hd)