Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Karol Herbst <kherbst@redhat.com>, Ben Skeggs <bskeggs@redhat.com>,
        Sasha Levin <sashal@kernel.org>,
        dri-devel@lists.freedesktop.org, nouveau@lists.freedesktop.org
Subject: [PATCH AUTOSEL 5.9 34/35] drm/nouveau/gem: fix "refcount_t: underflow; use-after-free"
Date:   Mon,  2 Nov 2020 20:18:39 -0500
Message-Id: <20201103011840.182814-34-sashal@kernel.org>
In-Reply-To: <20201103011840.182814-1-sashal@kernel.org>
References: <20201103011840.182814-1-sashal@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Karol Herbst <kherbst@redhat.com>

[ 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>
---
 drivers/gpu/drm/nouveau/nouveau_gem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

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;
 	}
 
-- 
2.27.0