On Fri, Aug 04, 2023 at 09:21:28AM +0200, Eric Dumazet wrote:

quoted

+/**
+ * dev_set_hwtstamp_phylib() - Change hardware timestamping of NIC
+ *     or of attached phylib PHY
+ * @dev: Network device
+ * @cfg: Timestamping configuration structure
+ * @extack: Netlink extended ack message structure, for error reporting
+ *
+ * Helper for enforcing a common policy that phylib timestamping, if available,
+ * should take precedence in front of hardware timestamping provided by the
+ * netdev. If the netdev driver needs to perform specific actions even for PHY
+ * timestamping to work properly (a switch port must trap the timestamped
+ * frames and not forward them), it must set IFF_SEE_ALL_HWTSTAMP_REQUESTS in
+ * dev->priv_flags.
+ */
+static int dev_set_hwtstamp_phylib(struct net_device *dev,
+                                  struct kernel_hwtstamp_config *cfg,
+                                  struct netlink_ext_ack *extack)
+{
+       const struct net_device_ops *ops = dev->netdev_ops;
+       bool phy_ts = phy_has_hwtstamp(dev->phydev);
+       struct kernel_hwtstamp_config old_cfg = {};
+       bool changed = false;
+       int err;
+
+       cfg->source = phy_ts ? HWTSTAMP_SOURCE_PHYLIB : HWTSTAMP_SOURCE_NETDEV;
+
+       if (!phy_ts || (dev->priv_flags & IFF_SEE_ALL_HWTSTAMP_REQUESTS)) {
+               err = ops->ndo_hwtstamp_get(dev, &old_cfg);

old_cfg.ifr is NULL at this point.

This causes a crash later in generic_hwtstamp_ioctl_lower()

    ifrr.ifr_ifru = kernel_cfg->ifr->ifr_ifru;

Thanks for reporting. My control flow is all wrong, it seems. I've sent
this patch for addressing the breakage:

https://lore.kernel.org/netdev/20230804134939.3109763-1-vladimir.oltean@nxp.com/ (local)

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel