From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Thu, 12 Jul 2018 17:04:14 +0200
Subject: drm/client: Fix double free in error path
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Git-commit: cf19fa2cfa4e9b5458b6f3503c5317dd1a2bfbae
Patch-mainline: v4.19-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

This fixes a static checker warning:

	drivers/gpu/drm/drm_client.c:289 drm_client_buffer_create()
	error: double free of 'buffer'

Extend drm_client_buffer_delete() to handle the case when there's no
dumb buffer attached and drop the extra kfree.

Fixes: c76f0f7cb546 ("drm: Begin an API for in-kernel clients")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20180712150414.46908-1-noralf@tronnes.org

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/drm_client.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/gpu/drm/drm_client.c
+++ b/drivers/gpu/drm/drm_client.c
@@ -218,7 +218,9 @@ static void drm_client_buffer_delete(str
 	if (buffer->gem)
 		drm_gem_object_put_unlocked(buffer->gem);
 
-	drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);
+	if (buffer->handle)
+		drm_mode_destroy_dumb(dev, buffer->handle, buffer->client->file);
+
 	kfree(buffer);
 }
 
@@ -243,7 +245,7 @@ drm_client_buffer_create(struct drm_clie
 	dumb_args.bpp = drm_format_plane_cpp(format, 0) * 8;
 	ret = drm_mode_create_dumb(dev, &dumb_args, client->file);
 	if (ret)
-		goto err_free;
+		goto err_delete;
 
 	buffer->handle = dumb_args.handle;
 	buffer->pitch = dumb_args.pitch;
@@ -276,8 +278,6 @@ drm_client_buffer_create(struct drm_clie
 
 err_delete:
 	drm_client_buffer_delete(buffer);
-err_free:
-	kfree(buffer);
 
 	return ERR_PTR(ret);
 }