[PATCH 2.6.15-rc3] Fix NULL-reference in DRM

[PATCH 2.6.15-rc3] Fix NULL-reference in DRM

[Takashi Iwai]

This patch fixes the NULL pointer reference in DRM.
SiS driver tries to allocate a big chunk of memory, but the return
value is never checked.

Reported in Novell bugzilla #132271:
https://bugzilla.novell.com/show_bug.cgi?id=132271

From: Egbert Eich <eich@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/drivers/char/drm/drm_context.c b/drivers/char/drm/drm_context.c
--- a/drivers/char/drm/drm_context.c
+++ b/drivers/char/drm/drm_context.c
@@ -432,7 +432,10 @@ int drm_addctx(struct inode *inode, stru
 
 	if (ctx.handle != DRM_KERNEL_CONTEXT) {
 		if (dev->driver->context_ctor)
-			dev->driver->context_ctor(dev, ctx.handle);
+			if (!dev->driver->context_ctor(dev, ctx.handle)) {
+				DRM_DEBUG( "Running out of ctxs or memory.\n");
+				return -ENOMEM;
+			}
 	}
 
 	ctx_entry = drm_alloc(sizeof(*ctx_entry), DRM_MEM_CTXLIST);