[PATCH] drm/bridge: it6505: Move a variable assignment behind a null pointer check in receive_timing_debugfs_show()

[Markus Elfring]

Date: Sun, 16 Apr 2023 17:30:46 +0200

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the function “receive_timing_debugfs_show”.

Thus avoid the risk for undefined behaviour by moving the assignment
for the variable “vid” behind the null pointer check.

This issue was detected by using the Coccinelle software.

Fixes: b5c84a9edcd418cd055becad6a22439e7c5e3bf8 ("drm/bridge: add it6505 driver")
Signed-off-by: Markus Elfring <elfring at users.sourceforge.net>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index abaf6e23775e..45f579c365e7 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -3207,7 +3207,7 @@ static ssize_t receive_timing_debugfs_show(struct file *file, char __user *buf,
 					   size_t len, loff_t *ppos)
 {
 	struct it6505 *it6505 = file->private_data;
-	struct drm_display_mode *vid = &it6505->video_info;
+	struct drm_display_mode *vid;
 	u8 read_buf[READ_BUFFER_SIZE];
 	u8 *str = read_buf, *end = read_buf + READ_BUFFER_SIZE;
 	ssize_t ret, count;
@@ -3216,6 +3216,7 @@ static ssize_t receive_timing_debugfs_show(struct file *file, char __user *buf,
 		return -ENODEV;

 	it6505_calc_video_info(it6505);
+	vid = &it6505->video_info;
 	str += scnprintf(str, end - str, "---video timing---\n");
 	str += scnprintf(str, end - str, "PCLK:%d.%03dMHz\n",
 			 vid->clock / 1000, vid->clock % 1000);
--
2.40.0