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From:   Michael Grzeschik <m.grzeschik@pengutronix.de>
To:     p.zabel@pengutronix.de, airlied@linux.ie,
        gregkh@linuxfoundation.org
Cc:     linux-kernel@vger.kernel.org, linux@armlinux.org.uk,
        dri-devel@lists.freedesktop.org, rafael@kernel.org,
        kernel@pengutronix.de
Subject: [PATCH 1/3] ipuv3-crtc: add remove action for devres data
Date:   Tue,  2 Apr 2019 15:49:02 +0200
Message-Id: <20190402134904.588-2-m.grzeschik@pengutronix.de>
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 <20190402134904.588-1-m.grzeschik@pengutronix.de>
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The destroy function in drm_mode_config_cleanup will remove the objects
in ipu-drm-core by calling its destroy functions if the bind function
fails. The drm_crtc is also part of the devres allocated ipu_crtc
object. The ipu_crtc object will already be cleaned up if the bind for
the crtc fails. This leads drm_crtc_cleanup try to clean already freed
memory.

We fix this issue by adding the devres action ipu_crtc_remove_head which
will remove its head from the objects in ipu-drm-core which then never
calls its destroy function anymore.

Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
---
 drivers/gpu/drm/imx/ipuv3-crtc.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/imx/ipuv3-crtc.c b/drivers/gpu/drm/imx/ipuv3-crtc.c
index ec3602ebbc1cd..fa1ee33a43d77 100644
--- a/drivers/gpu/drm/imx/ipuv3-crtc.c
+++ b/drivers/gpu/drm/imx/ipuv3-crtc.c
@@ -429,6 +429,14 @@ static int ipu_crtc_init(struct ipu_crtc *ipu_crtc,
 	return ret;
 }
 
+static void ipu_crtc_remove_head(void *data)
+{
+	struct ipu_crtc *ipu_crtc = data;
+	struct drm_crtc *crtc = &ipu_crtc->base;
+
+	list_del(&crtc->head);
+}
+
 static int ipu_drm_bind(struct device *dev, struct device *master, void *data)
 {
 	struct ipu_client_platformdata *pdata = dev->platform_data;
@@ -440,6 +448,10 @@ static int ipu_drm_bind(struct device *dev, struct device *master, void *data)
 	if (!ipu_crtc)
 		return -ENOMEM;
 
+	ret = devm_add_action(dev, ipu_crtc_remove_head, ipu_crtc);
+	if (ret)
+		return ret;
+
 	ipu_crtc->dev = dev;
 
 	ret = ipu_crtc_init(ipu_crtc, pdata, drm);
-- 
2.20.1