Comment by Aloisius

Might want to update it if you used the blog post explanation because it's incorrect as justinfrankel noted below. From the post:

    tcp_now   = 4,294,960,000  (frozen at pre-overflow value)

The mistake in the blog post is timer isn't wrapped, even though it notes it should be:

    timer     = 4,294,960,000 + 30,000 = 4,294,990,000 - MAX_INT = 22,704

Therefore:

    TSTMP_GEQ(4294960000, 22704)
    = 4294960000 - 22704
    = 4294937296
    = 4294937296 >= 0 ?  → true! (not false)

This is a bug of course, but it would cause sockets in TCP_WAIT state to be reaped anytime tcp_gc() is called, regardless of whether 2*MSL has passed or not. This only happens though if tcp_now gets stuck after 4,294,937,296 ms from boot.

A bug similar to what the blog described can happen however if tcp_now gets stuck at least 30 seconds before it it would have wrapped. Since tcp_now is only updated if there is TCP traffic, this can happen if there is no TCP traffic for at least 30 seconds before before it would roll over (MAX_INT ms from boot).

It's should be easy to prevent the latter from happening with some TCP traffic, though reaping TCP_WAIT connections early isn't great either.