From mboxrd@z Thu Jan 1 00:00:00 1970 From: Junio C Hamano Subject: Re: AAARGH bisection is hard (Re: [2.6.39 regression] X locks up hard right after logging in) Date: Fri, 13 May 2011 11:48:54 -0700 Message-ID: <7vliya77xl.fsf@alter.siamese.dyndns.org> References: <4DCD79A0.7000500@kdbg.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Johannes Sixt , Andrew Lutomirski , Christian Couder , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, git@vger.kernel.org, Shuang He To: Linus Torvalds Return-path: In-Reply-To: (Linus Torvalds's message of "Fri, 13 May 2011 11:41:46 -0700") Sender: git-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Linus Torvalds writes: > When you say that v2.6.38 is good, that means that everything that can > be reached from 2.6.38 is good. > > NOT AT ALL the same thing as "git bisect requires v2.6.38" would be. > > The "requires v2.6.38" would basically say that anything that doesn't > contain v2.6.38 is "off-limits". It's fine to call them "good", but > that's not the same thing as "git bisect good v2.6.38". > > Why? > > Think about it. It's the "reachable from v2.6.38" vs "cannot reach > v2.6.38" difference. That's a HUGE difference. Could you please clarify "off-limits"? Do you mean "anything before v2.6.38 did not even have this feature, so the result of testing a version in that range does not give us any information"? The feature didn't even exist, so a bug can never trigger, and seeing "good" from such a version does not mean everything reachable from it is good? Upon seeing "bad" result from a version before v2.6.38, what can we conclude? The breakage cannot possibly come from the feature that is being checked, so the procedure to check itself is busted?