[ewg] Re: OFED 1.2 beta blocking bugs

[Sean Hefty]

>From a quick look at the code, it does look like there are some races
> in ipoib_multicast.c.  The place where a QP is actually attached to a
> group is essentially (trimming debug prints):
> 
> 		if (test_and_set_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags))
> 			return 0;
> 
> 		ret = ipoib_mcast_attach(dev, be16_to_cpu(mcast->mcmember.mlid),
> 					 &mcast->mcmember.mgid);
> 
> and the place where a QP is detached is:
> 
> 	if (test_and_clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
> 		ret = ipoib_mcast_detach(dev, be16_to_cpu(mcast->mcmember.mlid),
> 					 &mcast->mcmember.mgid);

Going back to 2.6.20 (pre-multicast changes), this area of the code looks like 
it has the same race.  Was IPoIB HA testing done on 2.6.20 or earlier versions 
of the code, and if so, were any issues found?  (I'm not sure we've found all of 
the problems yet.)

- Sean