From: KhaiWenTan <khai.wen.tan@xxxxxxxxxxxxxxx> commit 675faf5a14c14a2be0b870db30a70764df81e2df upstream. 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> Reviewed-by: Simon Horman <horms@xxxxxxxxxx> Link: https://patch.msgid.link/20240918061422.1589662-1-khai.wen.tan@xxxxxxxxxxxxxxx Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_tc.c @@ -396,6 +396,7 @@ static int tc_setup_cbs(struct stmmac_pr return ret; priv->plat->tx_queues_cfg[queue].mode_to_use = MTL_QUEUE_DCB; + return 0; } /* Final adjustments for HW */ Patches currently in stable-queue which might be from khai.wen.tan@xxxxxxxxxxxxxxx are queue-6.10/net-stmmac-fix-zero-division-error-when-disabling-tc-cbs.patch