2016-11-11 16:26:30

by Colin King

Subject: [PATCH] drm/atomic: fix memory leak when fetching format name

From: Colin Ian King <[email protected]>

drm_get_format_name allocates memory that is not currently free'd
when printing the state. Fix this by kfree'ing the memory after
use.

Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpu/drm/drm_atomic.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
index f5ea7db..1d5e86a 100644
--- a/drivers/gpu/drm/drm_atomic.c
+++ b/drivers/gpu/drm/drm_atomic.c
@@ -917,9 +917,10 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
if (state->fb) {
struct drm_framebuffer *fb = state->fb;
int i, n = drm_format_num_planes(fb->pixel_format);
+ char *format_name = drm_get_format_name(fb->pixel_format);

- drm_printf(p, "\t\tformat=%s\n",
- drm_get_format_name(fb->pixel_format));
+ drm_printf(p, "\t\tformat=%s\n", format_name);
+ kfree(format_name);
drm_printf(p, "\t\tsize=%dx%d\n", fb->width, fb->height);
drm_printf(p, "\t\tlayers:\n");
for (i = 0; i < n; i++) {
--
2.10.2

2016-11-11 17:18:06

by Eric Engestrom

Subject: Re: [PATCH] drm/atomic: fix memory leak when fetching format name

On Friday, 2016-11-11 16:26:22 +0000, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> drm_get_format_name allocates memory that is not currently free'd
> when printing the state. Fix this by kfree'ing the memory after
> use.

You are correct, but there are more cases of this, and another fix
has been chosen. See this patch [1] for the fix and the rest of that
thread [2] for the discussion.

I'll send v4 (rebase and a missed `const`) as soon as I have the time,
but the usage will remain the same as in v3.

Cheers,
Eric

[1] https://lists.freedesktop.org/archives/dri-devel/2016-November/123250.html
[2] https://lists.freedesktop.org/archives/dri-devel/2016-November/thread.html#122845

>
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/gpu/drm/drm_atomic.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index f5ea7db..1d5e86a 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -917,9 +917,10 @@ static void drm_atomic_plane_print_state(struct drm_printer *p,
> if (state->fb) {
> struct drm_framebuffer *fb = state->fb;
> int i, n = drm_format_num_planes(fb->pixel_format);
> + char *format_name = drm_get_format_name(fb->pixel_format);
>
> - drm_printf(p, "\t\tformat=%s\n",
> - drm_get_format_name(fb->pixel_format));
> + drm_printf(p, "\t\tformat=%s\n", format_name);
> + kfree(format_name);
> drm_printf(p, "\t\tsize=%dx%d\n", fb->width, fb->height);
> drm_printf(p, "\t\tlayers:\n");
> for (i = 0; i < n; i++) {
> --
> 2.10.2
>