This is a note to let you know that I've just added the patch titled gve: fix the wrong AdminQ buffer overflow check to the 5.14-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: gve-fix-the-wrong-adminq-buffer-overflow-check.patch and it can be found in the queue-5.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 02b5cc94cb7ebdd99623783f534dc0e0c06ba4e5 Author: Haiyue Wang <haiyue.wang@xxxxxxxxx> Date: Wed Jul 14 15:34:59 2021 +0800 gve: fix the wrong AdminQ buffer overflow check [ Upstream commit 63a9192b8fa1ea55efeba1f18fad52bb24d9bf12 ] The 'tail' pointer is also free-running count, so it needs to be masked as 'adminq_prod_cnt' does, to become an index value of AdminQ buffer. Fixes: 5cdad90de62c ("gve: Batch AQ commands for creating and destroying queues.") Signed-off-by: Haiyue Wang <haiyue.wang@xxxxxxxxx> Reviewed-by: Catherine Sullivan <csully@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/ethernet/google/gve/gve_adminq.c b/drivers/net/ethernet/google/gve/gve_adminq.c index 5bb56b454541..f089d33dd48e 100644 --- a/drivers/net/ethernet/google/gve/gve_adminq.c +++ b/drivers/net/ethernet/google/gve/gve_adminq.c @@ -322,7 +322,8 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv, tail = ioread32be(&priv->reg_bar0->adminq_event_counter); // Check if next command will overflow the buffer. - if (((priv->adminq_prod_cnt + 1) & priv->adminq_mask) == tail) { + if (((priv->adminq_prod_cnt + 1) & priv->adminq_mask) == + (tail & priv->adminq_mask)) { int err; // Flush existing commands to make room. @@ -332,7 +333,8 @@ static int gve_adminq_issue_cmd(struct gve_priv *priv, // Retry. tail = ioread32be(&priv->reg_bar0->adminq_event_counter); - if (((priv->adminq_prod_cnt + 1) & priv->adminq_mask) == tail) { + if (((priv->adminq_prod_cnt + 1) & priv->adminq_mask) == + (tail & priv->adminq_mask)) { // This should never happen. We just flushed the // command queue so there should be enough space. return -ENOMEM;