On Mon, Nov 15, 2021 at 07:08:30PM +0100, Ansuel Smith wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
> > master
> > head: debe436e77c72fcee804fb867f275e6d31aa999c
> > commit: 5654ec78dd7e64b1e04777b24007344329e6a63b net: dsa: qca8k: rework
> > rgmii delay logic and scan for cpu port 6
> > config: i386-randconfig-m021-20211025 (attached as .config)
> > compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
> >
> > If you fix the issue, kindly add following tag as appropriate
> > Reported-by: kernel test robot
> > Reported-by: Dan Carpenter
> >
>
> This should already be fixed by 06dd34a628ae5b6a839b757e746de165d6789ca8
> Can you confirm this?
>
No, it doesn't fix the problem. The check is either useless and should
be removed or there is an out of bounds bug. Checking for an out of
bounds *after* you've already written to the memory is *never* useful.
regards,
dan carpenter
> > smatch warnings:
> > drivers/net/dsa/qca8k.c:944 qca8k_parse_port_config() error: testing array
> > offset 'cpu_port_index' after use.
> >
> > vim +/cpu_port_index +944 drivers/net/dsa/qca8k.c
> >
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 934 static int
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 935
> > qca8k_parse_port_config(struct qca8k_priv *priv)
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 936 {
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 937int port, cpu_port_index =
> > 0, ret;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 938struct device_node *port_dn;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 939phy_interface_t mode;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 940struct dsa_port *dp;
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 941u32 delay;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 942
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 943/* We have 2 CPU port.
> > Check them */
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 @944for (port = 0; port <
> > QCA8K_NUM_PORTS && cpu_port_index < QCA8K_NUM_CPU_PORTS; port++) {
> >
> > ^
> > Assume cpu_port_index = QCA8K_NUM_CPU_PORTS - 1;
> >
> >
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 945/* Skip every other
> > port */
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 946if (port != 0 &&
> > port != 6)
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 947continue;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 948
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 949dp =
> > dsa_to_port(priv->ds, port);
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 950port_dn = dp->dn;
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 951cpu_port_index++;
> > ^
> > cpu_port_index is now out of bounds.
> >
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 952
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 953if
> > (!of_device_is_available(port_dn))
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 954continue;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 955
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 956ret =
> > of_get_phy_mode(port_dn, );
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 957if (ret)
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 958continue;
> > 6c43809bf1bee7 Ansuel Smith 2021-10-14 959
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 960switch (mode) {
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 961case
> > PHY_INTERFACE_MODE_RGMII:
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 962case
> > PHY_INTERFACE_MODE_RGMII_ID:
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 963case
> > PHY_INTERFACE_MODE_RGMII_TXID:
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 964case
> > PHY_INTERFACE_MODE_RGMII_RXID:
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 965delay = 0;
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 966
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 967if
> > (!of_property_read_u32(port_dn, "tx-internal-delay-ps", ))
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 968/*
> > Switch regs accept value in ns, convert ps to ns */
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 969
> > delay = delay / 1000;
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 970else if
> > (mode == PHY_INTERFACE_MODE_RGMII_ID ||
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 971
> > mode == PHY_INTERFACE_MODE_RGMII_TXID)
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 972
> > delay = 1;
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 973
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 974if (delay >
> > QCA8K_MAX_DELAY) {
> > 5654ec78dd7e64 Ansuel Smith 2021-10-14 975
