On Apr 24 17:06, Vinicius Costa Gomes wrote: > 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.
The same would then be possible on igb as well, wouldn't it? > If there's anything that makes this impossible/extremely unlikely, the > patch looks good: > > Acked-by: Vinicius Costa Gomes <[email protected]> > > > Cheers, > -- > Vinicius Corinna
