> -----Original Message----- > From: Liming Sun <limings@xxxxxxxxxx> > Sent: Wednesday, 26 April 2023 17:24 > To: Vadim Pasternak <vadimp@xxxxxxxxxx>; David Thompson > <davthompson@xxxxxxxxxx>; Hans de Goede <hdegoede@xxxxxxxxxx>; > Mark Gross <markgross@xxxxxxxxxx> > Cc: Liming Sun <limings@xxxxxxxxxx>; platform-driver-x86@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx > Subject: [PATCH v1 1/1] platform/mellanox: fix potential race in mlxbf-tmfifo > driver > > 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 <limings@xxxxxxxxxx> Reviewed-by: Vadim Pasternak <vadimp@xxxxxxxxxx> > --- > 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 91a077c35b8b..a79318e90a13 100644 > --- a/drivers/platform/mellanox/mlxbf-tmfifo.c > +++ b/drivers/platform/mellanox/mlxbf-tmfifo.c > @@ -784,7 +784,7 @@ 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. */ @@ -980,9 +980,13 @@ > 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; > @@ -1302,6 +1306,9 @@ 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; > > -- > 2.30.1
