linux-kernel - [PATCH 5.4 54/92] drm/msm: fix memleak on release

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Message-Id: <20191211150245.038759780@linuxfoundation.org>
Date:   Wed, 11 Dec 2019 16:05:45 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jordan Crouse <jcrouse@...eaurora.org>,
        Rob Clark <robdclark@...il.com>,
        Johan Hovold <johan@...nel.org>,
        Sean Paul <seanpaul@...omium.org>
Subject: [PATCH 5.4 54/92] drm/msm: fix memleak on release

From: Johan Hovold <johan@...nel.org>

commit a64fc11b9a520c55ca34d82e5ca32274f49b6b15 upstream.

If a process is interrupted while accessing the "gpu" debugfs file and
the drm device struct_mutex is contended, release() could return early
and fail to free related resources.

Note that the return value from release() is ignored.

Fixes: 4f776f4511c7 ("drm/msm/gpu: Convert the GPU show function to use the GPU state")
Cc: stable <stable@...r.kernel.org>     # 4.18
Cc: Jordan Crouse <jcrouse@...eaurora.org>
Cc: Rob Clark <robdclark@...il.com>
Reviewed-by: Rob Clark <robdclark@...il.com>
Signed-off-by: Johan Hovold <johan@...nel.org>
Signed-off-by: Sean Paul <seanpaul@...omium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191010131333.23635-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/gpu/drm/msm/msm_debugfs.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

--- a/drivers/gpu/drm/msm/msm_debugfs.c
+++ b/drivers/gpu/drm/msm/msm_debugfs.c
@@ -47,12 +47,8 @@ static int msm_gpu_release(struct inode
 	struct msm_gpu_show_priv *show_priv = m->private;
 	struct msm_drm_private *priv = show_priv->dev->dev_private;
 	struct msm_gpu *gpu = priv->gpu;
-	int ret;
-
-	ret = mutex_lock_interruptible(&show_priv->dev->struct_mutex);
-	if (ret)
-		return ret;
 
+	mutex_lock(&show_priv->dev->struct_mutex);
 	gpu->funcs->gpu_state_put(show_priv->state);
 	mutex_unlock(&show_priv->dev->struct_mutex);