From 0a853a02d268ae7355e559043e4dea1a1b2be9a5 Mon Sep 17 00:00:00 2001 From: Liming Sun Date: Thu, 13 Apr 2023 08:32:24 -0400 Subject: [PATCH] UBUNTU: SAUCE: mlxbf-tmfifo: fix potential race X-NVConfidentiality: public BugLink: https://bugs.launchpad.net/bugs/2016039 The fix adds memory barrier for the 'is_ready' flag and the 'vq' pointer in mlxbf_tmfifo_virtio_find_vqs() to avoid potential race due to out-of-order memory write. Signed-off-by: Liming Sun Acked-by: Bartlomiej Zolnierkiewicz Acked-by: Tim Gardner [bzolnier: this patch also contains a fix for mlxbf_tmfifo_create_vdev() failure case] Signed-off-by: Bartlomiej Zolnierkiewicz --- drivers/platform/mellanox/mlxbf-tmfifo.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/platform/mellanox/mlxbf-tmfifo.c b/drivers/platform/mellanox/mlxbf-tmfifo.c index 97956c9c9d4c..19d539fc99ae 100644 --- a/drivers/platform/mellanox/mlxbf-tmfifo.c +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c @@ -922,7 +922,7 @@ 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. */ @@ -1119,9 +1119,13 @@ static int mlxbf_tmfifo_virtio_find_vqs(struct virtio_device *vdev, goto error; } + vq->priv = vring; + + /* Make vq update visible before using it. */ + virtio_mb(false); + vqs[i] = vq; vring->vq = vq; - vq->priv = vring; } return 0; @@ -1426,6 +1430,9 @@ static int mlxbf_tmfifo_probe(struct platform_device *pdev) mod_timer(&fifo->timer, jiffies + MLXBF_TMFIFO_TIMER_INTERVAL); + /* Make all updates visible before the 'is_ready' flag. */ + virtio_mb(false); + fifo->is_ready = 1; return 0; -- 2.14.1