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From:   Jiasheng Jiang <jiasheng@iscas.ac.cn>
To:     robin.murphy@arm.com, liviu.dudau@arm.com, brian.starkey@arm.com,
        airlied@gmail.com, daniel@ffwll.ch
Cc:     linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
        Jiasheng Jiang <jiasheng@iscas.ac.cn>
Subject: [PATCH] drm: mali-dp: Add check for kzalloc
Date:   Thu,  8 Dec 2022 11:15:06 +0800
Message-Id: <20221208031506.3211-1-jiasheng@iscas.ac.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

As kzalloc may fail and return NULL pointer, the "mw_state" can be NULL.
If the layout of struct malidp_mw_connector_state ever changes, it
will cause NULL poineter derefernce of "&mw_state->base".
Therefore, the "mw_state" should be check whether it is NULL in order
to improve the robust.

Fixes: 8cbc5caf36ef ("drm: mali-dp: Add writeback connector")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
---
 drivers/gpu/drm/arm/malidp_mw.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/arm/malidp_mw.c b/drivers/gpu/drm/arm/malidp_mw.c
index ef76d0e6ee2f..fe4474c2ddcf 100644
--- a/drivers/gpu/drm/arm/malidp_mw.c
+++ b/drivers/gpu/drm/arm/malidp_mw.c
@@ -72,7 +72,11 @@ static void malidp_mw_connector_reset(struct drm_connector *connector)
 		__drm_atomic_helper_connector_destroy_state(connector->state);
 
 	kfree(connector->state);
-	__drm_atomic_helper_connector_reset(connector, &mw_state->base);
+
+	if (mw_state)
+		__drm_atomic_helper_connector_reset(connector, &mw_state->base);
+	else
+		__drm_atomic_helper_connector_reset(connector, NULL);
 }
 
 static enum drm_connector_status
-- 
2.25.1