On Sun, 2013-12-15 at 21:44 -0500, Alan Stern wrote: > On Sun, 15 Dec 2013, James Bottomley wrote: > > > No, I was thinking of the two thread scan bug (i.e. two scan threads) > > not one scan and one remove, which is a bug in the old code. This is a > > race between put and get when the kref is incremented from zero (an > > illegal operation which triggers a warn on). > > > > The way to mediate this is to check for the kref already being zero > > condition, like below. > > Yes, that seems reasonable. Consider now: Having done this, to what > extent do starget->reap_ref and starget->state really need to be > protected by the host_lock? Maybe only the linked lists require > protection. (I haven't checked.) Yes, I think so, but that can be done as an enhancement patch after the fact. > Can you post a single, combined patch incorporating all your proposed > changes? It's little hard to review them in pieces... Sure, I'll repost what I have. > Alan Stern > > P.S.: Would you agree that the phrase "pretty astonishing cockup" did > indeed turn out to be appropriate? :-) Objection, m'lud, my learned friend is leading the witness ... James -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
