| Message ID | 20250318161702.2982063-1-andriy.shevchenko@linux.intel.com (mailing list archive) |
|---|---|
| State | New |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,v1,1/1] net: usb: asix: ax88772: Increase phy_name size | expand |
> struct ax88172a_private { > struct mii_bus *mdio; > struct phy_device *phydev; > - char phy_name[20]; > + char phy_name[MII_BUS_ID_SIZE + 5]; Could you explain the + 5? https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/davicom/dm9051.c#L1156 https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/freescale/fec_main.c#L2454 https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/xilinx/ll_temac.h#L348 The consensus seems to be + 3. Andrew
On Tue, Mar 18, 2025 at 05:49:05PM +0100, Andrew Lunn wrote: ... > > - char phy_name[20]; > > + char phy_name[MII_BUS_ID_SIZE + 5]; > > Could you explain the + 5? > > https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/davicom/dm9051.c#L1156 > https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/freescale/fec_main.c#L2454 > https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/xilinx/ll_temac.h#L348 > > The consensus seems to be + 3. u16, gcc can't proove the range, it assumes 65536 is the maximum. include/linux/phy.h:312:20: note: directive argument in the range [0, 65535]
On Tue, Mar 18, 2025 at 06:54:48PM +0200, Andy Shevchenko wrote: > On Tue, Mar 18, 2025 at 05:49:05PM +0100, Andrew Lunn wrote: > > ... > > > > - char phy_name[20]; > > > + char phy_name[MII_BUS_ID_SIZE + 5]; > > > > Could you explain the + 5? > > > > https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/davicom/dm9051.c#L1156 > > https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/freescale/fec_main.c#L2454 > > https://elixir.bootlin.com/linux/v6.13.7/source/drivers/net/ethernet/xilinx/ll_temac.h#L348 > > > > The consensus seems to be + 3. > > u16, gcc can't proove the range, it assumes 65536 is the maximum. > > include/linux/phy.h:312:20: note: directive argument in the range [0, 65535] How about after ret = asix_read_phy_addr(dev, priv->use_embdphy); if (ret < 0) goto free; add if (ret > 31) { netdev_err(dev->net, "Invalid PHY ID %d\n", ret); return -ENODEV; } and see if GCC can follow that? Andrew
diff --git a/drivers/net/usb/ax88172a.c b/drivers/net/usb/ax88172a.c index e47bb125048d..7844eb02a4c7 100644 --- a/drivers/net/usb/ax88172a.c +++ b/drivers/net/usb/ax88172a.c @@ -18,7 +18,7 @@ struct ax88172a_private { struct mii_bus *mdio; struct phy_device *phydev; - char phy_name[20]; + char phy_name[MII_BUS_ID_SIZE + 5]; u16 phy_addr; u16 oldmode; int use_embdphy; @@ -308,7 +308,7 @@ static int ax88172a_reset(struct usbnet *dev) rx_ctl); /* Connect to PHY */ - snprintf(priv->phy_name, 20, PHY_ID_FMT, + snprintf(priv->phy_name, sizeof(priv->phy_name), PHY_ID_FMT, priv->mdio->id, priv->phy_addr); priv->phydev = phy_connect(dev->net, priv->phy_name,
GCC compiler (Debian 14.2.0-17) is not happy about printing into a short buffer (when build with `make W=1`): drivers/net/usb/ax88172a.c: In function ‘ax88172a_reset’: include/linux/phy.h:312:20: error: ‘%s’ directive output may be truncated writing up to 60 bytes into a region of size 20 [-Werror=format-truncation=] Indeed, the buffer size is chosen based on some assumptions, while in general the assigned name might not fit. Increase the buffer to cover maximum length of the parameters. With that, change snprintf() to use sizeof() instead of hard coded number. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- drivers/net/usb/ax88172a.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)