Messages in this thread | | | Date | Fri, 25 Jun 2021 14:59:06 +0200 | From | Maxime Ripard <> | Subject | Re: Kernel Panic in skb_release_data using genet |
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Hi Florian,
Sorry for the late reply
On Thu, Jun 10, 2021 at 02:33:17PM -0700, Florian Fainelli wrote: > On 6/2/2021 6:28 AM, Maxime Ripard wrote: > > On Tue, Jun 01, 2021 at 11:33:18AM +0200, nicolas saenz julienne wrote: > >> On Mon, 2021-05-31 at 19:36 -0700, Florian Fainelli wrote: > >>>> That is also how I boot my Pi4 at home, and I suspect you are right, if > >>>> the VPU does not shut down GENET's DMA, and leaves buffer addresses in > >>>> the on-chip descriptors that point to an address space that is managed > >>>> totally differently by Linux, then we can have a serious problem and > >>>> create some memory corruption when the ring is being reclaimed. I will > >>>> run a few experiments to test that theory and there may be a solution > >>>> using the SW_INIT reset controller to have a big reset of the controller > >>>> before handing it over to the Linux driver. > >>> > >>> Adding a WARN_ON(reg & DMA_EN) in bcmgenet_dma_disable() has not shown > >>> that the TX or RX DMA have been left running during the hand over from > >>> the VPU to the kernel. I checked out drm-misc-next-2021-05-17 to reduce > >>> as much as possible the differences between your set-up and my set-up > >>> but so far have not been able to reproduce the crash in booting from NFS > >>> repeatedly, I will try again. > >> > >> FWIW I can reproduce the error too. That said it's rather hard to reproduce, > >> something in the order of 1 failure every 20 tries. > > > > Yeah, it looks like it's only from a cold boot and comes in "bursts", > > where you would get like 5 in a row and be done with it for a while. > > Here are two patches that you could try exclusive from one another > > 1) Limit GENET to a single queue > > diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c > b/drivers/net/ethernet/broadcom/genet/bcmgenet.c > index fcca023f22e5..e400c12e6868 100644 > --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c > +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c > @@ -3652,6 +3652,12 @@ static int bcmgenet_change_carrier(struct > net_device *dev, bool new_carrier) > return 0; > } > > +static u16 bcmgenet_select_queue(struct net_device *dev, struct sk_buff > *skb, > + struct net_device *sb_dev) > +{ > + return 0; > +} > + > static const struct net_device_ops bcmgenet_netdev_ops = { > .ndo_open = bcmgenet_open, > .ndo_stop = bcmgenet_close, > @@ -3666,6 +3672,7 @@ static const struct net_device_ops > bcmgenet_netdev_ops = { > #endif > .ndo_get_stats = bcmgenet_get_stats, > .ndo_change_carrier = bcmgenet_change_carrier, > + .ndo_select_queue = bcmgenet_select_queue, > }; > > /* Array of GENET hardware parameters/characteristics */ > > 2) Ensure that all TX/RX queues are disabled upon DMA initialization > > diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c > b/drivers/net/ethernet/broadcom/genet/bcmgenet.c > index fcca023f22e5..7f8a5996fbbb 100644 > --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c > +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c > @@ -3237,15 +3237,21 @@ static void bcmgenet_get_hw_addr(struct > bcmgenet_priv *priv, > /* Returns a reusable dma control register value */ > static u32 bcmgenet_dma_disable(struct bcmgenet_priv *priv) > { > + unsigned int i; > u32 reg; > u32 dma_ctrl; > > /* disable DMA */ > dma_ctrl = 1 << (DESC_INDEX + DMA_RING_BUF_EN_SHIFT) | DMA_EN; > + for (i = 0; i < priv->hw_params->tx_queues; i++) > + dma_ctrl |= (1 << (i + DMA_RING_BUF_EN_SHIFT)); > reg = bcmgenet_tdma_readl(priv, DMA_CTRL); > reg &= ~dma_ctrl; > bcmgenet_tdma_writel(priv, reg, DMA_CTRL); > > + dma_ctrl = 1 << (DESC_INDEX + DMA_RING_BUF_EN_SHIFT) | DMA_EN; > + for (i = 0; i < priv->hw_params->rx_queues; i++) > + dma_ctrl |= (1 << (i + DMA_RING_BUF_EN_SHIFT)); > reg = bcmgenet_rdma_readl(priv, DMA_CTRL); > reg &= ~dma_ctrl; > bcmgenet_rdma_writel(priv, reg, DMA_CTRL);
I had a bunch of issues popping up today so I took the occasion to test those patches. The first one doesn't change anything, I still had the crash occurring with it. With the second applied (in addition), it seems like it's fixed. I'll keep testing and will let you know.
Maxime [unhandled content-type:application/pgp-signature] | |