drm/msm: fix memleak on release

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@vger.kernel.org>     # 4.18
Cc: Jordan Crouse <jcrouse@codeaurora.org>
Cc: Rob Clark <robdclark@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191010131333.23635-2-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/msm/msm_debugfs.c b/drivers/gpu/drm/msm/msm_debugfs.c
index d756436..989465e 100644 (file)
--- a/drivers/gpu/drm/msm/msm_debugfs.c
+++ b/drivers/gpu/drm/msm/msm_debugfs.c
@@ -53,12 +53,8 @@ static int msm_gpu_release(struct inode *inode, struct file *file)
        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);