linux-kernel - [PATCH RESEND] drm/msm/dpu: Delete a variable initialisation before a null pointer check in two functions

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Message-ID: <54c30a69-71cf-4582-9086-50eb0d39f273@web.de>
Date: Sun, 2 Mar 2025 21:56:00 +0100
From: Markus Elfring <Markus.Elfring@....de>
To: kernel-janitors@...r.kernel.org, freedreno@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
 Abhinav Kumar <quic_abhinavk@...cinc.com>,
 Archit Taneja <architt@...eaurora.org>, Daniel Vetter <daniel@...ll.ch>,
 David Airlie <airlied@...il.com>,
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
 Jeykumar Sankaran <jsanka@...eaurora.org>,
 Jordan Crouse <jordan@...micpenguin.net>,
 Marijn Suijten <marijn.suijten@...ainline.org>,
 Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
 Simona Vetter <simona@...ll.ch>, Vinod Koul <vkoul@...nel.org>
Cc: cocci@...ia.fr, LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH RESEND] drm/msm/dpu: Delete a variable initialisation before a
 null pointer check in two functions

From: Markus Elfring <elfring@...rs.sourceforge.net>
Date: Tue, 11 Apr 2023 18:24:24 +0200

The address of a data structure member was determined before
a corresponding null pointer check in the implementation of
the functions “dpu_hw_pp_enable_te” and “dpu_hw_pp_get_vsync_info”.

Thus avoid the risk for undefined behaviour by removing extra
initialisations for the variable “c” (also because it was already
reassigned with the same value behind this pointer check).

This issue was detected by using the Coccinelle software.

Fixes: 25fdd5933e4c ("drm/msm: Add SDM845 DPU support")
Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
index 0fcad9760b6f..870ab3ebbc94 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_pingpong.c
@@ -176,7 +176,7 @@ static int dpu_hw_pp_enable_te(struct dpu_hw_pingpong *pp, bool enable)
 static int dpu_hw_pp_connect_external_te(struct dpu_hw_pingpong *pp,
 		bool enable_external_te)
 {
-	struct dpu_hw_blk_reg_map *c = &pp->hw;
+	struct dpu_hw_blk_reg_map *c;
 	u32 cfg;
 	int orig;

@@ -221,7 +221,7 @@ static int dpu_hw_pp_get_vsync_info(struct dpu_hw_pingpong *pp,

 static u32 dpu_hw_pp_get_line_count(struct dpu_hw_pingpong *pp)
 {
-	struct dpu_hw_blk_reg_map *c = &pp->hw;
+	struct dpu_hw_blk_reg_map *c;
 	u32 height, init;
 	u32 line = 0xFFFF;

--
2.40.0