[PATCH 16/30] staging: sync: Fix error paths

[John Stultz]

From: Rebecca Schultz Zavin <rebecca at android.com>

Check the return value of get_unused_fd to make sure a valid
file descriptor is returned.

Make sure to call put_unused_fd even if an error occurs before
the fd can be used.

Cc: Maarten Lankhorst <maarten.lankhorst at canonical.com>
Cc: Erik Gilling <konkers at android.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Rob Clark <robclark at gmail.com>
Cc: Sumit Semwal <sumit.semwal at linaro.org>
Cc: Greg KH <gregkh at linuxfoundation.org>
Cc: dri-devel at lists.freedesktop.org
Cc: Android Kernel Team <kernel-team at android.com>
Signed-off-by: Rebecca Schultz Zavin <rebecca at android.com>
Signed-off-by: John Stultz <john.stultz at linaro.org>
---
 drivers/staging/android/sync.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/android/sync.c b/drivers/staging/android/sync.c
index 61c27bd..c4a3c1d 100644
--- a/drivers/staging/android/sync.c
+++ b/drivers/staging/android/sync.c
@@ -647,8 +647,13 @@ static long sync_fence_ioctl_merge(struct sync_fence *fence, unsigned long arg)
 	struct sync_fence *fence2, *fence3;
 	struct sync_merge_data data;
 
-	if (copy_from_user(&data, (void __user *)arg, sizeof(data)))
-		return -EFAULT;
+	if (fd < 0)
+		return fd;
+
+	if (copy_from_user(&data, (void __user *)arg, sizeof(data))) {
+		err = -EFAULT;
+		goto err_put_fd;
+	}
 
 	fence2 = sync_fence_fdget(data.fd2);
 	if (fence2 == NULL) {
-- 
1.7.10.4