Patchwork vhost: fix double free on device stop

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Submitter Michael S. Tsirkin
Date June 21, 2011, 5:10 p.m.
Message ID <20110621171044.GA16869@redhat.com>
Download mbox | patch
Permalink /patch/101339/
State New
Headers show

Comments

Michael S. Tsirkin - June 21, 2011, 5:10 p.m.
vhost dev stop failed to clear the log field.
Typically not an issue as dev start overwrites this field,
but if logging gets disabled before the following start,
it doesn't so this causes a double free.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 hw/vhost.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
Michael S. Tsirkin - June 21, 2011, 5:40 p.m.
On Tue, Jun 21, 2011 at 08:10:44PM +0300, Michael S. Tsirkin wrote:
> vhost dev stop failed to clear the log field.
> Typically not an issue as dev start overwrites this field,
> but if logging gets disabled before the following start,
> it doesn't so this causes a double free.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

Um, this fixed double free but added another one.
Not sure why did it work for me :(
Sent a fixed v2

> ---
>  hw/vhost.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/vhost.c b/hw/vhost.c
> index 80f771e..1fbf2e5 100644
> --- a/hw/vhost.c
> +++ b/hw/vhost.c
> @@ -784,5 +784,9 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
>  
>      hdev->started = false;
>      qemu_free(hdev->log);
> +    if (hdev->log) {
> +        qemu_free(hdev->log);
> +    }
> +    hdev->log = NULL;
>      hdev->log_size = 0;
>  }
> -- 
> 1.7.5.53.gc233e

Patch

diff --git a/hw/vhost.c b/hw/vhost.c
index 80f771e..1fbf2e5 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -784,5 +784,9 @@  void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
 
     hdev->started = false;
     qemu_free(hdev->log);
+    if (hdev->log) {
+        qemu_free(hdev->log);
+    }
+    hdev->log = NULL;
     hdev->log_size = 0;
 }