[PATCH net v5] net: xilinx: axienet: Fix IRQ coalescing packet count overflow

[PATCH net v5] net: xilinx: axienet: Fix IRQ coalescing packet count overflow

[Sean Anderson]

If coalesce_count is greater than 255 it will not fit in the register and
will overflow. This can be reproduced by running

    # ethtool -C ethX rx-frames 256

which will result in a timeout of 0us instead. Fix this by checking for
invalid values and reporting an error.

Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
---

Changes in v5:
- Fix typo in commit message

Changes in v4:
- Fix checking rx twice instead of rx and tx

Changes in v3:
- Validate and reject instead of silently clamping

Changes in v2:
- Use FIELD_MAX to extract the max value from the mask
- Expand the commit message with an example on how to reproduce this
  issue

 drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
index 0f4b02fe6f85..ae743991117c 100644
--- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
+++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
@@ -2056,6 +2056,12 @@ axienet_ethtools_set_coalesce(struct net_device *ndev,
 		return -EBUSY;
 	}
 
+	if (ecoalesce->rx_max_coalesced_frames > 255 ||
+	    ecoalesce->tx_max_coalesced_frames > 255) {
+		NL_SET_ERR_MSG(extack, "frames must be less than 256");
+		return -EINVAL;
+	}
+
 	if (ecoalesce->rx_max_coalesced_frames)
 		lp->coalesce_count_rx = ecoalesce->rx_max_coalesced_frames;
 	if (ecoalesce->rx_coalesce_usecs)
-- 
2.35.1.1320.gc452695387.dirty

RE: [PATCH net v5] net: xilinx: axienet: Fix IRQ coalescing packet count overflow

[Pandey, Radhey Shyam]

> -----Original Message-----
> From: Sean Anderson <sean.anderson@linux.dev>
> Sent: Monday, January 13, 2025 10:00 PM
> To: Pandey, Radhey Shyam <radhey.shyam.pandey@amd.com>; Nelson, Shannon
> <Shannon.Nelson@amd.com>; David S . Miller <davem@davemloft.net>; Eric
> Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo
> Abeni <pabeni@redhat.com>; netdev@vger.kernel.org
> Cc: linux-arm-kernel@lists.infradead.org; Simon Horman <horms@kernel.org>;
> Simek, Michal <michal.simek@amd.com>; linux-kernel@vger.kernel.org; Daniel
> Borkmann <daniel@iogearbox.net>; Sean Anderson <sean.anderson@linux.dev>
> Subject: [PATCH net v5] net: xilinx: axienet: Fix IRQ coalescing packet count
> overflow
> 
> If coalesce_count is greater than 255 it will not fit in the register and
> will overflow. This can be reproduced by running
> 
>     # ethtool -C ethX rx-frames 256
> 
> which will result in a timeout of 0us instead. Fix this by checking for
> invalid values and reporting an error.
> 
> Fixes: 8a3b7a252dca ("drivers/net/ethernet/xilinx: added Xilinx AXI Ethernet driver")
> Signed-off-by: Sean Anderson <sean.anderson@linux.dev>
> Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>

Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@amd.com>
Thanks!
> ---
> 
> Changes in v5:
> - Fix typo in commit message
> 
> Changes in v4:
> - Fix checking rx twice instead of rx and tx
> 
> Changes in v3:
> - Validate and reject instead of silently clamping
> 
> Changes in v2:
> - Use FIELD_MAX to extract the max value from the mask
> - Expand the commit message with an example on how to reproduce this
>   issue
> 
>  drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 0f4b02fe6f85..ae743991117c 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -2056,6 +2056,12 @@ axienet_ethtools_set_coalesce(struct net_device *ndev,
>  		return -EBUSY;
>  	}
> 
> +	if (ecoalesce->rx_max_coalesced_frames > 255 ||
> +	    ecoalesce->tx_max_coalesced_frames > 255) {
> +		NL_SET_ERR_MSG(extack, "frames must be less than 256");
> +		return -EINVAL;
> +	}
> +
>  	if (ecoalesce->rx_max_coalesced_frames)
>  		lp->coalesce_count_rx = ecoalesce->rx_max_coalesced_frames;
>  	if (ecoalesce->rx_coalesce_usecs)
> --
> 2.35.1.1320.gc452695387.dirty

Re: [PATCH net v5] net: xilinx: axienet: Fix IRQ coalescing packet count overflow

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Mon, 13 Jan 2025 11:30:00 -0500 you wrote:
> If coalesce_count is greater than 255 it will not fit in the register and
> will overflow. This can be reproduced by running
> 
>     # ethtool -C ethX rx-frames 256
> 
> which will result in a timeout of 0us instead. Fix this by checking for
> invalid values and reporting an error.
> 
> [...]

Here is the summary with links:
  - [net,v5] net: xilinx: axienet: Fix IRQ coalescing packet count overflow
    https://git.kernel.org/netdev/net/c/c17ff476f53a

You are awesome, thank you!
-- 
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