From: Liming Sun Date: Wed, 26 Apr 2023 14:23:44 +0000 (-0400) Subject: platform/mellanox: fix potential race in mlxbf-tmfifo driver X-Git-Tag: v6.1.33~153 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=61c3962ab1f9647998bab2aa47fb29bcc214d41a;p=users%2Fdwmw2%2Flinux.git platform/mellanox: fix potential race in mlxbf-tmfifo driver [ Upstream commit 3d43f9f639542fadfb28f40b509bf147a6624d48 ] This commit adds memory barrier for the 'vq' update in function mlxbf_tmfifo_virtio_find_vqs() to avoid potential race due to out-of-order memory write. It also adds barrier for the 'is_ready' flag to make sure the initializations are visible before this flag is checked. Signed-off-by: Liming Sun Reviewed-by: Vadim Pasternak Link: https://lore.kernel.org/r/b98c0ab61d644ba38fa9b3fd1607b138b0dd820b.1682518748.git.limings@nvidia.com Signed-off-by: Hans de Goede Signed-off-by: Sasha Levin --- diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c index 1ae3c56b66b09..b2e19f30a928b 100644 --- a/drivers/platform/mellanox/mlxbf-tmfifo.c +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c @@ -765,7 +765,7 @@ static void mlxbf_tmfifo_rxtx(struct mlxbf_tmfifo_vring *vring, bool is_rx) fifo = vring->fifo; /* Return if vdev is not ready. */ - if (!fifo->vdev[devid]) + if (!fifo || !fifo->vdev[devid]) return; /* Return if another vring is running. */ @@ -961,9 +961,13 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev, vq->num_max = vring->num; + vq->priv = vring; + + /* Make vq update visible before using it. */ + virtio_mb(false); + vqs[i] = vq; vring->vq = vq; - vq->priv = vring; } return 0; @@ -1260,6 +1264,9 @@ static int mlxbf_tmfifo_probe(struct platform_device *pdev) mod_timer(&fifo->timer, jiffies + MLXBF_TMFIFO_TIMER_INTERVAL); + /* Make all updates visible before setting the 'is_ready' flag. */ + virtio_mb(false); + fifo->is_ready = true; return 0;