[PATCH 6.4 229/800] drm/bridge: it6505: Move a variable assignment behind a null pointer check in receive_timing_debugfs_show()

Greg Kroah-Hartman
2023-07-16T20:03:32Z

From: Markus Elfring <elfring@users.sourceforge.net>

[ Upstream commit 0be05a75de2916421e88e0d64b001984f54df0bd ]

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: b5c84a9edcd4 ("drm/bridge: add it6505 driver")
Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Link: https://patchwork.freedesktop.org/patch/msgid/fa69384f-1485-142b-c4ee-3df54ac68a89@web.de
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 abaf6e23775eb..45f579c365e7f 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);
--
2.39.2