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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        =?UTF-8?q?Jos=C3=A9=20Exp=C3=B3sito?= <jose.exposito89@gmail.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.16 170/200] drm/msm/dpu: invalid parameter check in dpu_setup_dspp_pcc
Date:   Mon, 31 Jan 2022 11:57:13 +0100
Message-Id: <20220131105239.275458113@linuxfoundation.org>
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From: José Expósito <jose.exposito89@gmail.com>

[ Upstream commit 170b22234d5495f5e0844246e23f004639ee89ba ]

The function performs a check on the "ctx" input parameter, however, it
is used before the check.

Initialize the "base" variable after the sanity check to avoid a
possible NULL pointer dereference.

Fixes: 4259ff7ae509e ("drm/msm/dpu: add support for pcc color block in dpu driver")
Addresses-Coverity-ID: 1493866 ("Null pointer dereference")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Link: https://lore.kernel.org/r/20220109192431.135949-1-jose.exposito89@gmail.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.c
index a98e964c3b6fa..355894a3b48c3 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dspp.c
@@ -26,9 +26,16 @@ static void dpu_setup_dspp_pcc(struct dpu_hw_dspp *ctx,
 		struct dpu_hw_pcc_cfg *cfg)
 {
 
-	u32 base = ctx->cap->sblk->pcc.base;
+	u32 base;
 
-	if (!ctx || !base) {
+	if (!ctx) {
+		DRM_ERROR("invalid ctx %pK\n", ctx);
+		return;
+	}
+
+	base = ctx->cap->sblk->pcc.base;
+
+	if (!base) {
 		DRM_ERROR("invalid ctx %pK pcc base 0x%x\n", ctx, base);
 		return;
 	}
-- 
2.34.1