* [Qemu-devel] [PATCH] check for bs->drv in bdrv_flush
@ 2009-03-28 18:39 Christoph Hellwig
2009-03-29 1:32 ` Anthony Liguori
0 siblings, 1 reply; 3+ messages in thread
From: Christoph Hellwig @ 2009-03-28 18:39 UTC (permalink / raw)
To: qemu-devel
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>
Index: qemu/block.c
===================================================================
--- qemu.orig/block.c 2009-03-19 21:48:12.180978074 +0100
+++ qemu/block.c 2009-03-19 21:48:53.228977807 +0100
@@ -979,6 +979,8 @@ const char *bdrv_get_device_name(BlockDr
void bdrv_flush(BlockDriverState *bs)
{
+ if (!bs->drv)
+ return;
if (bs->drv->bdrv_flush)
bs->drv->bdrv_flush(bs);
if (bs->backing_hd)
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] check for bs->drv in bdrv_flush
2009-03-28 18:39 [Qemu-devel] [PATCH] check for bs->drv in bdrv_flush Christoph Hellwig
@ 2009-03-29 1:32 ` Anthony Liguori
2009-03-29 7:31 ` Christoph Hellwig
0 siblings, 1 reply; 3+ messages in thread
From: Anthony Liguori @ 2009-03-29 1:32 UTC (permalink / raw)
To: qemu-devel
Christoph Hellwig wrote:
> 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.
>
Applied. Thanks.
FWIW, I plan to include qemu-io once you rebase the series to use
IOVectors instead of struct iovec. It looks like a useful tool!
Regards,
Anthony Liguori
> Signed-off-by: Christoph Hellwig <hch@lst.de>
>
> Index: qemu/block.c
> ===================================================================
> --- qemu.orig/block.c 2009-03-19 21:48:12.180978074 +0100
> +++ qemu/block.c 2009-03-19 21:48:53.228977807 +0100
> @@ -979,6 +979,8 @@ const char *bdrv_get_device_name(BlockDr
>
> void bdrv_flush(BlockDriverState *bs)
> {
> + if (!bs->drv)
> + return;
> if (bs->drv->bdrv_flush)
> bs->drv->bdrv_flush(bs);
> if (bs->backing_hd)
>
>
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH] check for bs->drv in bdrv_flush
2009-03-29 1:32 ` Anthony Liguori
@ 2009-03-29 7:31 ` Christoph Hellwig
0 siblings, 0 replies; 3+ messages in thread
From: Christoph Hellwig @ 2009-03-29 7:31 UTC (permalink / raw)
To: qemu-devel
On Sat, Mar 28, 2009 at 08:32:35PM -0500, Anthony Liguori wrote:
> Christoph Hellwig wrote:
> >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.
> >
>
> Applied. Thanks.
>
> FWIW, I plan to include qemu-io once you rebase the series to use
> IOVectors instead of struct iovec. It looks like a useful tool!
The repost already uses QEMUIOVectors, I'll resend it with a
formal description.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2009-03-29 7:31 UTC | newest]
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2009-03-28 18:39 [Qemu-devel] [PATCH] check for bs->drv in bdrv_flush Christoph Hellwig
2009-03-29 1:32 ` Anthony Liguori
2009-03-29 7:31 ` Christoph Hellwig
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