From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Yuntao Liu <liuyuntao10@huawei.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 269/575] virtio-gpu: fix possible memory allocation failure
Date:   Mon, 15 Nov 2021 17:59:54 +0100
Message-Id: <20211115165353.075689326@linuxfoundation.org>
In-Reply-To: <20211115165343.579890274@linuxfoundation.org>
References: <20211115165343.579890274@linuxfoundation.org>
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From: liuyuntao <liuyuntao10@huawei.com>

[ Upstream commit 5bd4f20de8acad37dbb3154feb34dbc36d506c02 ]

When kmem_cache_zalloc in virtio_gpu_get_vbuf fails, it will return
an error code. But none of its callers checks this error code, and
a core dump will take place.

Considering many of its callers can't handle such error, I add
a __GFP_NOFAIL flag when calling kmem_cache_zalloc to make sure
it won't fail, and delete those unused error handlings.

Fixes: dc5698e80cf724 ("Add virtio gpu driver.")
Signed-off-by: Yuntao Liu <liuyuntao10@huawei.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210828104321.3410312-1-liuyuntao10@huawei.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/virtio/virtgpu_vq.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index 07945ca238e2d..5e40fa0f5e8f2 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -91,9 +91,7 @@ virtio_gpu_get_vbuf(struct virtio_gpu_device *vgdev,
 {
 	struct virtio_gpu_vbuffer *vbuf;
 
-	vbuf = kmem_cache_zalloc(vgdev->vbufs, GFP_KERNEL);
-	if (!vbuf)
-		return ERR_PTR(-ENOMEM);
+	vbuf = kmem_cache_zalloc(vgdev->vbufs, GFP_KERNEL | __GFP_NOFAIL);
 
 	BUG_ON(size > MAX_INLINE_CMD_SIZE ||
 	       size < sizeof(struct virtio_gpu_ctrl_hdr));
@@ -147,10 +145,6 @@ static void *virtio_gpu_alloc_cmd_resp(struct virtio_gpu_device *vgdev,
 
 	vbuf = virtio_gpu_get_vbuf(vgdev, cmd_size,
 				   resp_size, resp_buf, cb);
-	if (IS_ERR(vbuf)) {
-		*vbuffer_p = NULL;
-		return ERR_CAST(vbuf);
-	}
 	*vbuffer_p = vbuf;
 	return (struct virtio_gpu_command *)vbuf->buf;
 }
-- 
2.33.0