Andrew Lunn <[email protected]> writes: > On Tue, Apr 23, 2024 at 12:24:54PM +0200, Corinna Vinschen wrote: >> During successful probe, igc logs this: >> >> [ 5.133667] igc 0000:01:00.0 (unnamed net_device) (uninitialized): PHC >> added >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ >> The reason is that igc_ptp_init() is called very early, even before >> register_netdev() has been called. So the netdev_info() call works >> on a partially uninitialized netdev. >> >> Fix this by calling igc_ptp_init() after register_netdev(), right >> after the media autosense check, just as in igb. Add a comment, >> just as in igb. > > The network stack can start sending and receiving packet before > register_netdev() returns. This is typical of NFS root for example. Is > there anything in igc_ptp_init() which could cause such packet > transfers to explode? >
There might be a very narrow window (probably impossible?), what I can see is: 1. the netdevice is exposed to userspace; 2. userspace does the SIOCSHWTSTAMP ioctl() to enable TX timestamps; 3. userspace sends a packet that is going to be timestamped; if this happens before igc_ptp_init() is called, adapter->ptp_tx_lock is going to be uninitialized, and (3) is going to crash. If there's anything that makes this impossible/extremely unlikely, the patch looks good: Acked-by: Vinicius Costa Gomes <[email protected]> Cheers, -- Vinicius
