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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, fuyufan <fuyufan@huawei.com>,
        =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= 
        <ville.syrjala@linux.intel.com>, Maxime Ripard <maxime@cerno.tech>
Subject: [PATCH 5.16 080/227] drm/atomic: Dont pollute crtc_state->mode_blob with error pointers
Date:   Mon, 21 Feb 2022 09:48:19 +0100
Message-Id: <20220221084937.524263514@linuxfoundation.org>
In-Reply-To: <20220221084934.836145070@linuxfoundation.org>
References: <20220221084934.836145070@linuxfoundation.org>
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From: Ville Syrjälä <ville.syrjala@linux.intel.com>

commit 439cf34c8e0a8a33d8c15a31be1b7423426bc765 upstream.

Make sure we don't assign an error pointer to crtc_state->mode_blob
as that will break all kinds of places that assume either NULL or a
valid pointer (eg. drm_property_blob_put()).

Cc: stable@vger.kernel.org
Reported-by: fuyufan <fuyufan@huawei.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220209091928.14766-1-ville.syrjala@linux.intel.com
Acked-by: Maxime Ripard <maxime@cerno.tech>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/drm_atomic_uapi.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/drivers/gpu/drm/drm_atomic_uapi.c
+++ b/drivers/gpu/drm/drm_atomic_uapi.c
@@ -76,15 +76,17 @@ int drm_atomic_set_mode_for_crtc(struct
 	state->mode_blob = NULL;
 
 	if (mode) {
+		struct drm_property_blob *blob;
+
 		drm_mode_convert_to_umode(&umode, mode);
-		state->mode_blob =
-			drm_property_create_blob(state->crtc->dev,
-						 sizeof(umode),
-						 &umode);
-		if (IS_ERR(state->mode_blob))
-			return PTR_ERR(state->mode_blob);
+		blob = drm_property_create_blob(crtc->dev,
+						sizeof(umode), &umode);
+		if (IS_ERR(blob))
+			return PTR_ERR(blob);
 
 		drm_mode_copy(&state->mode, mode);
+
+		state->mode_blob = blob;
 		state->enable = true;
 		drm_dbg_atomic(crtc->dev,
 			       "Set [MODE:%s] for [CRTC:%d:%s] state %p\n",