Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix missing mutex unlock on error path

[Markus Elfring]

…
> Add a mutex unlock call.

How do you think about a wording variant like the following?

   Extend the exception handling so that the missed mutex_unlock() call
   will be performed finally.


Regards,
Markus

Re: [PATCH] drm: bridge: cdns-mhdp8546: Fix missing mutex unlock on error path

[Dmitry Baryshkov]

On Fri, Apr 19, 2024 at 02:36:37PM +0300, Aleksandr Mishin wrote:
> In cdns_mhdp_atomic_enable(), there is an error return on failure of
> drm_mode_duplicate() which leads to the mutex remaining locked.
> Add a mutex unlock call.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 935a92a1c400 ("drm: bridge: cdns-mhdp8546: Fix possible null pointer 
> dereference")
> Signed-off-by: Aleksandr Mishin 
> ---
> This patch is against drm-misc-next branch of drm-misc repo.
> 
>  drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 6 --
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> 


Reviewed-by: Dmitry Baryshkov 


-- 
With best wishes
Dmitry

[PATCH] drm: bridge: cdns-mhdp8546: Fix missing mutex unlock on error path

[Aleksandr Mishin]

In cdns_mhdp_atomic_enable(), there is an error return on failure of
drm_mode_duplicate() which leads to the mutex remaining locked.
Add a mutex unlock call.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 935a92a1c400 ("drm: bridge: cdns-mhdp8546: Fix possible null pointer 
dereference")
Signed-off-by: Aleksandr Mishin 
---
This patch is against drm-misc-next branch of drm-misc repo.

 drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c | 6 --
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c 
b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
index 8a91ef0ae065..65a4bd09d9c6 100644
--- a/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
+++ b/drivers/gpu/drm/bridge/cadence/cdns-mhdp8546-core.c
@@ -2059,8 +2059,10 @@ static void cdns_mhdp_atomic_enable(struct drm_bridge 
*bridge,
mhdp_state = to_cdns_mhdp_bridge_state(new_state);
 
mhdp_state->current_mode = drm_mode_duplicate(bridge->dev, mode);
-   if (!mhdp_state->current_mode)
-   return;
+   if (!mhdp_state->current_mode) {
+   ret = -EINVAL;
+   goto out;
+   }
 
drm_mode_set_name(mhdp_state->current_mode);
 
-- 
2.30.2