linux-kernel - [PATCH] drm/omapdrm: check the return value of kzalloc()

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Message-ID: <tencent_E01412E12D4A66FFB02064CC9CB9141CDE08@qq.com>
Date:   Thu, 24 Mar 2022 18:58:04 +0800
From:   xkernel.wang@...mail.com
To:     tomba@...nel.org, airlied@...ux.ie, daniel@...ll.ch
Cc:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        Xiaoke Wang <xkernel.wang@...mail.com>
Subject: [PATCH] drm/omapdrm: check the return value of kzalloc()

From: Xiaoke Wang <xkernel.wang@...mail.com>

kzalloc() is a memory allocation function which can return NULL when
some internal memory errors happen. So it is better to check it.
Besides, to properly handle the error, another check is added for the
return of omap_irq_wait_init().

Signed-off-by: Xiaoke Wang <xkernel.wang@...mail.com>
---
 drivers/gpu/drm/omapdrm/omap_crtc.c | 12 ++++++++----
 drivers/gpu/drm/omapdrm/omap_irq.c  |  3 +++
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/omapdrm/omap_crtc.c b/drivers/gpu/drm/omapdrm/omap_crtc.c
index 06a719c..12c0008 100644
--- a/drivers/gpu/drm/omapdrm/omap_crtc.c
+++ b/drivers/gpu/drm/omapdrm/omap_crtc.c
@@ -166,10 +166,14 @@ void omap_crtc_set_enabled(struct drm_crtc *crtc, bool enable)
 	dispc_mgr_enable(priv->dispc, channel, enable);
 	omap_crtc->enabled = enable;
 
-	ret = omap_irq_wait(dev, wait, msecs_to_jiffies(100));
-	if (ret) {
-		dev_err(dev->dev, "%s: timeout waiting for %s\n",
-				omap_crtc->name, enable ? "enable" : "disable");
+	if (!wait) {
+		dev_err(dev->dev, "%s: out of memory\n", omap_crtc->name);
+	} else {
+		ret = omap_irq_wait(dev, wait, msecs_to_jiffies(100));
+		if (ret) {
+			dev_err(dev->dev, "%s: timeout waiting for %s\n",
+					omap_crtc->name, enable ? "enable" : "disable");
+		}
 	}
 
 	if (omap_crtc->channel == OMAP_DSS_CHANNEL_DIGIT) {
diff --git a/drivers/gpu/drm/omapdrm/omap_irq.c b/drivers/gpu/drm/omapdrm/omap_irq.c
index 4aca14d..a234462 100644
--- a/drivers/gpu/drm/omapdrm/omap_irq.c
+++ b/drivers/gpu/drm/omapdrm/omap_irq.c
@@ -45,6 +45,9 @@ struct omap_irq_wait * omap_irq_wait_init(struct drm_device *dev,
 	struct omap_irq_wait *wait = kzalloc(sizeof(*wait), GFP_KERNEL);
 	unsigned long flags;
 
+	if (!wait)
+		return NULL;
+
 	init_waitqueue_head(&wait->wq);
 	wait->irqmask = irqmask;
 	wait->count = count;
--