Patch "virtio-gpu: fix possible memory allocation failure" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    virtio-gpu: fix possible memory allocation failure

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio-gpu-fix-possible-memory-allocation-failure.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit c702f73717f0569bec8e270f98dd5b6619725e20
Author: liuyuntao <liuyuntao10@xxxxxxxxxx>
Date:   Sat Aug 28 18:43:21 2021 +0800

    virtio-gpu: fix possible memory allocation failure
    
    [ 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@xxxxxxxxxx>
    Link: http://patchwork.freedesktop.org/patch/msgid/20210828104321.3410312-1-liuyuntao10@xxxxxxxxxx
    Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

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;
 }