From: Eric Anholt <eric@anholt.net>
Date: Thu, 9 Feb 2017 17:23:34 +0000 (-0800)
Subject: drm/vc4: Fix OOPSes from trying to cache a partially constructed BO.
X-Git-Tag: archive/raspbian/4.9.51-1+rpi1~5^2~358
X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=94f398391a9c24d7405fc4f8ff47d85a8dbd230f;p=linux-4.9.git

drm/vc4: Fix OOPSes from trying to cache a partially constructed BO.

If a CMA allocation failed, the partially constructed BO would be
unreferenced through the normal path, and we might choose to put it in
the BO cache.  If we then reused it before it expired from the cache,
the kernel would OOPS.

Signed-off-by: Eric Anholt <eric@anholt.net>
Fixes: c826a6e10644 ("drm/vc4: Add a BO cache.")
---

diff --git a/drivers/gpu/drm/vc4/vc4_bo.c b/drivers/gpu/drm/vc4/vc4_bo.c
index fd83a2807656..b5802f7acf6e 100644
--- a/drivers/gpu/drm/vc4/vc4_bo.c
+++ b/drivers/gpu/drm/vc4/vc4_bo.c
@@ -322,6 +322,14 @@ void vc4_free_object(struct drm_gem_object *gem_bo)
 		goto out;
 	}
 
+	/* If this object was partially constructed but CMA allocation
+	 * had failed, just free it.
+	 */
+	if (!bo->base.vaddr) {
+		vc4_bo_destroy(bo);
+		goto out;
+	}
+
 	cache_list = vc4_get_cache_list_for_size(dev, gem_bo->size);
 	if (!cache_list) {
 		vc4_bo_destroy(bo);