component: fix bug with legacy API

Sachin Kamat reports that "component: add support for component match
array" broke Exynos DRM due to a NULL pointer deref.  Fix this.

Reported-by: Sachin Kamat <sachin.kamat@samsung.com>
Tested-by: Sachin Kamat <sachin.kamat@samsung.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/base/component.c b/drivers/base/component.c
index b4236daed4fa..f748430bb654 100644
--- a/drivers/base/component.c
+++ b/drivers/base/component.c
@@ -293,10 +293,12 @@ int component_master_add_with_match(struct device *dev,
         if (ops->add_components && match)
                 return -EINVAL;
 
-        /* Reallocate the match array for its true size */
-        match = component_match_realloc(dev, match, match->num);
-        if (IS_ERR(match))
-                return PTR_ERR(match);
+        if (match) {
+                /* Reallocate the match array for its true size */
+                match = component_match_realloc(dev, match, match->num);
+                if (IS_ERR(match))
+                        return PTR_ERR(match);
+        }
 
         master = kzalloc(sizeof(*master), GFP_KERNEL);
         if (!master)