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Mon, 18 Aug 2025 02:32:08 -0700 (PDT) Received: from localhost.localdomain ([2401:4900:1cb8:46d9:adba:d08d:ac6:8cbb]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2446cb0f007sm75092045ad.69.2025.08.18.02.32.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Aug 2025 02:32:07 -0700 (PDT) From: Chandra Mohan Sundar To: alain.volmat@foss.st.com, mchehab@kernel.org, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, linux-media@vger.kernel.org, linux-arm-kernel@lists.infradead.org, shuah@kernel.org Cc: Chandra Mohan Sundar , linux-kernel-mentees@lists.linux.dev Subject: [PATCH] media: v4l: Fix dereference before NULL check Date: Mon, 18 Aug 2025 15:01:57 +0530 Message-ID: <20250818093159.612208-1-chandramohan.explore@gmail.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit In 'stm32_csi_start', 'csidev->s_subdev' is dereferenced directly while assigning a value to the 'src_pad'. However the same value is being checked against NULL at a later point of time indicating that there are chances that the value can be NULL. Move the dereference after the NULL check. Fixes: e7bad98c205d1 ("media: v4l: Convert the users of v4l2_get_link_freq to call it on a pad") Signed-off-by: Chandra Mohan Sundar --- drivers/media/platform/st/stm32/stm32-csi.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/media/platform/st/stm32/stm32-csi.c b/drivers/media/platform/st/stm32/stm32-csi.c index b69048144cc1..fd2b6dfbd44c 100644 --- a/drivers/media/platform/st/stm32/stm32-csi.c +++ b/drivers/media/platform/st/stm32/stm32-csi.c @@ -443,8 +443,7 @@ static void stm32_csi_phy_reg_write(struct stm32_csi_dev *csidev, static int stm32_csi_start(struct stm32_csi_dev *csidev, struct v4l2_subdev_state *state) { - struct media_pad *src_pad = - &csidev->s_subdev->entity.pads[csidev->s_subdev_pad_nb]; + struct media_pad *src_pad; const struct stm32_csi_mbps_phy_reg *phy_regs = NULL; struct v4l2_mbus_framefmt *sink_fmt; const struct stm32_csi_fmts *fmt; @@ -466,6 +465,7 @@ static int stm32_csi_start(struct stm32_csi_dev *csidev, if (!csidev->s_subdev) return -EIO; + src_pad = &csidev->s_subdev->entity.pads[csidev->s_subdev_pad_nb]; link_freq = v4l2_get_link_freq(src_pad, fmt->bpp, 2 * csidev->num_lanes); if (link_freq < 0) -- 2.43.0