linux-kernel - [PATCH 5.4 185/355] virtio-gpu: fix possible memory allocation failure

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Message-Id: <20211115165319.761853705@linuxfoundation.org>
Date:   Mon, 15 Nov 2021 18:01:49 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Yuntao Liu <liuyuntao10@...wei.com>,
        Gerd Hoffmann <kraxel@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 185/355] virtio-gpu: fix possible memory allocation failure

From: liuyuntao <liuyuntao10@...wei.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@...wei.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20210828104321.3410312-1-liuyuntao10@huawei.com
Signed-off-by: Gerd Hoffmann <kraxel@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.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 bb46e7a0f1b5d..0ca996e6fd5cb 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -80,9 +80,7 @@ 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);
 	vbuf->buf = (void *)vbuf + sizeof(*vbuf);
@@ -142,10 +140,6 @@ 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