From: Karol Herbst <kherbst@redhat.com>
Date: Tue, 6 Oct 2020 22:08:09 +0000 (+0200)
Subject: drm/nouveau/gem: fix "refcount_t: underflow; use-after-free"
X-Git-Tag: v5.9.7~31
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b74c934d47a6b2a868a519c37d19dfcd9ea0bfd5;p=thirdparty%2Fkernel%2Fstable.git

drm/nouveau/gem: fix "refcount_t: underflow; use-after-free"

[ Upstream commit 925681454d7b557d404b5d28ef4469fac1b2e105 ]

we can't use nouveau_bo_ref here as no ttm object was allocated and
nouveau_bo_ref mainly deals with that. Simply deallocate the object.

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c b/drivers/gpu/drm/nouveau/nouveau_gem.c
index 81f111ad3f4fd..124d3dcc5c590 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -198,7 +198,8 @@ nouveau_gem_new(struct nouveau_cli *cli, u64 size, int align, uint32_t domain,
 	 * to the caller, instead of a normal nouveau_bo ttm reference. */
 	ret = drm_gem_object_init(drm->dev, &nvbo->bo.base, size);
 	if (ret) {
-		nouveau_bo_ref(NULL, &nvbo);
+		drm_gem_object_release(&nvbo->bo.base);
+		kfree(nvbo);
 		return ret;
 	}