drm/savage: dereferencing an error pointer

commit f7741aa75e76440f4e9ecfe512feebe9bce33ca8 upstream.

A recent cleanup changed the kmalloc() + copy_from_user() to
memdup_user() but the error handling wasn't updated so we might call
kfree(-EFAULT) and crash.

Fixes: a6e3918bcdb1 ('GPU-DRM-Savage: Use memdup_user() rather than duplicating')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161012062227.GU12841@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/savage/savage_state.c b/drivers/gpu/drm/savage/savage_state.c
index 3dc0d8f..2db89be 100644 (file)
--- a/drivers/gpu/drm/savage/savage_state.c
+++ b/drivers/gpu/drm/savage/savage_state.c
@@ -1004,6 +1004,7 @@ int savage_bci_cmdbuf(struct drm_device *dev, void *data, struct drm_file *file_
                kvb_addr = memdup_user(cmdbuf->vb_addr, cmdbuf->vb_size);
                if (IS_ERR(kvb_addr)) {
                        ret = PTR_ERR(kvb_addr);
+                       kvb_addr = NULL;
                        goto done;
                }
                cmdbuf->vb_addr = kvb_addr;