[BUG] net: e100: possible data races in e100_watchdog()

[Jia-Ju Bai]

The call paths in Linux 4.16.7 that may raise data races are:

CPU0:
e100_set_multicast_list
    e100_exec_cb
        line 879: spin_lock_irqsave()
        e100_configure
            line 1139: nic->flags [READ]
            line 1148: nic->flags [READ]

CPU1:
e100_watchdog:
    line 1758, 1756: nic->flags [WRITE]

The READ operations in CPU0 are performed with holding a spinlock (line 
879), but the WRITE operation in CPU1 is performed without holding this 
spinlock, so it may cause data races here.

A possible fix is to add spin_lock_irqsave() in e100_watchdog().
I am not sure that whether this possible fix is correct, so I only 
report the data races.


Best wishes,
Jia-Ju Bai