Re: [PATCH net 1/1] net: stmmac: Fix zero-division error when disabling tc cbs

From: Tan, Khai Wen
Date: Tue Sep 17 2024 - 22:27:44 EST


On 12/9/2024 11:39 pm, Simon Horman wrote:
On Thu, Sep 12, 2024 at 04:37:30PM +0100, Simon Horman wrote:
On Thu, Sep 12, 2024 at 09:55:41AM +0800, KhaiWenTan wrote:
The commit b8c43360f6e4 ("net: stmmac: No need to calculate speed divider
when offload is disabled") allows the "port_transmit_rate_kbps" to be
set to a value of 0, which is then passed to the "div_s64" function when
tc-cbs is disabled. This leads to a zero-division error.

When tc-cbs is disabled, the idleslope, sendslope, and credit values the
credit values are not required to be configured. Therefore, adding a return
statement after setting the txQ mode to DCB when tc-cbs is disabled would
prevent a zero-division error.

Fixes: b8c43360f6e4 ("net: stmmac: No need to calculate speed divider when offload is disabled")
Cc: <stable@xxxxxxxxxxxxxxx>
Co-developed-by: Choong Yong Liang <yong.liang.choong@xxxxxxxxxxxxxxx>
Signed-off-by: Choong Yong Liang <yong.liang.choong@xxxxxxxxxxxxxxx>
Signed-off-by: KhaiWenTan <khai.wen.tan@xxxxxxxxxxxxxxx>
...

One more thing, if you do post an updated patch, please
be sure to wait until 24h after the original patch was posted.

https://docs.kernel.org/process/maintainer-netdev.html

Hi Simon,

Thanks for the clarification. Will be updating a version 2 for this patch.