linux-kernel - [PATCH][next] drm/atomic: avoid null pointer dereference on pointer crtc

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Message-Id: <20201116110316.269934-1-colin.king@canonical.com>
Date:   Mon, 16 Nov 2020 11:03:16 +0000
From:   Colin King <colin.king@...onical.com>
To:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Simon Ser <contact@...rsion.fr>,
        Sam Ravnborg <sam@...nborg.org>,
        dri-devel@...ts.freedesktop.org
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] drm/atomic: avoid null pointer dereference on pointer crtc

From: Colin Ian King <colin.king@...onical.com>

Since moving to the new debug helper functions we now have a debug message
that dereferences crtc to print a kernel debug message when crtc is null
and so this debug message will now cause a null pointer dereference. Since
this is a debug message it probably is just simplest to fix this by just
removing the debug message altogether.

Addresses-Coverity: ("Dereference after null check")
Fixes: e3aae683e861 ("drm: convert drm_atomic_uapi.c to new debug helpers")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/gpu/drm/drm_atomic_uapi.c | 5 -----
 1 file changed, 5 deletions(-)

diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
index 9df7f2a170e3..3fd84590560a 100644
--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -338,11 +338,6 @@ drm_atomic_set_crtc_for_connector(struct drm_connector_state *conn_state,
 			       "Link [CONNECTOR:%d:%s] state %p to [CRTC:%d:%s]\n",
 			       connector->base.id, connector->name,
 			       conn_state, crtc->base.id, crtc->name);
-	} else {
-		drm_dbg_atomic(crtc->dev,
-			       "Link [CONNECTOR:%d:%s] state %p to [NOCRTC]\n",
-			       connector->base.id, connector->name,
-			       conn_state);
 	}
 
 	return 0;
-- 
2.28.0