[PATCH 1/1] gpu: drm: qxl: fix use of uninitialized variable

[PATCH 1/1] gpu: drm: qxl: fix use of uninitialized variable

[Pan Bian]

In function qxl_release_alloc(), when kmalloc() returns a NULL pointer,
it returns value 0 and parameter *ret is uninitialized. 0 means no error
to the callers of qxl_release_alloc(). The callers keep going and will
try to reference the uninitialized variable. This patch fixes the bug,
returning "-ENOMEM" when kmalloc() fails.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188911

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/gpu/drm/qxl/qxl_release.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index cd83f05..e6daa70 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -133,7 +133,7 @@ static long qxl_fence_wait(struct fence *fence, bool intr, signed long timeout)
 	release = kmalloc(size, GFP_KERNEL);
 	if (!release) {
 		DRM_ERROR("Out of memory\n");
-		return 0;
+		return -ENOMEM;
 	}
 	release->base.ops = NULL;
 	release->type = type;
-- 
1.9.1

Re: [PATCH 1/1] gpu: drm: qxl: fix use of uninitialized variable

[Sean Paul]

On Sat, Dec 3, 2016 at 10:11 AM, Pan Bian <bianpan2016@163.com> wrote:
> In function qxl_release_alloc(), when kmalloc() returns a NULL pointer,
> it returns value 0 and parameter *ret is uninitialized. 0 means no error
> to the callers of qxl_release_alloc(). The callers keep going and will
> try to reference the uninitialized variable. This patch fixes the bug,
> returning "-ENOMEM" when kmalloc() fails.
>
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=188911
>
> Signed-off-by: Pan Bian <bianpan2016@163.com>

Applied to drm-misc, with subject prefix tweak s_gpu: drm: qxl_drm/qxl_

Thanks!

Sean

> ---
>  drivers/gpu/drm/qxl/qxl_release.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> index cd83f05..e6daa70 100644
> --- a/drivers/gpu/drm/qxl/qxl_release.c
> +++ b/drivers/gpu/drm/qxl/qxl_release.c
> @@ -133,7 +133,7 @@ static long qxl_fence_wait(struct fence *fence, bool intr, signed long timeout)
>         release = kmalloc(size, GFP_KERNEL);
>         if (!release) {
>                 DRM_ERROR("Out of memory\n");
> -               return 0;
> +               return -ENOMEM;
>         }
>         release->base.ops = NULL;
>         release->type = type;
> --
> 1.9.1
>
>