drm/msm: Defer fd_install in SUBMIT ioctl

[ Upstream commit f228534 ]

Avoid fd_install() until there are no more potential error paths, to
avoid put_unused_fd() after the fd is made visible to userspace.

Fixes: 68dc6c2 ("drm/msm: Fix submit error-path leaks")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>
Patchwork: https://patchwork.freedesktop.org/patch/665363/
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: Rob Clark

drivers/gpu/drm/msm/msm_gem_submit.c

@@ -869,12 +869,8 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 
 	if (ret == 0 && args->flags & MSM_SUBMIT_FENCE_FD_OUT) {
 		sync_file = sync_file_create(submit->user_fence);
-		if (!sync_file) {
+		if (!sync_file)
 			ret = -ENOMEM;
-		} else {
-			fd_install(out_fence_fd, sync_file->file);
-			args->fence_fd = out_fence_fd;
-		}
 	}
 
 	if (ret)
@@ -902,10 +898,14 @@ int msm_ioctl_gem_submit(struct drm_device *dev, void *data,
 out_unlock:
 	mutex_unlock(&queue->lock);
 out_post_unlock:
-	if (ret && (out_fence_fd >= 0)) {
-		put_unused_fd(out_fence_fd);
+	if (ret) {
+		if (out_fence_fd >= 0)
+			put_unused_fd(out_fence_fd);
 		if (sync_file)
 			fput(sync_file->file);
+	} else if (sync_file) {
+		fd_install(out_fence_fd, sync_file->file);
+		args->fence_fd = out_fence_fd;
 	}
 
 	if (!IS_ERR_OR_NULL(submit)) {