Re: LSan curiosity in t1300

From: Jeff King <peff@peff.net>
Date: Sep 8, 2022, 18:15 UTC
Message-ID: <YxoxRus2NjsYmM63@coredump.intra.peff.net>
In-Reply-To: <xmqq8rmtrbfq.fsf@gitster.g>

On Thu, Sep 08, 2022 at 11:03:05AM -0700, Junio C Hamano wrote:

Show 11 quoted lines

> > But if you run this in a debugger, you'll find that under -O2 the "key"
> > variable has been optimized out! So LSan is producing the wrong result
> > due to the optimization. It doesn't know that "key" is conceptually
> > still reachable.
> 
> Yikes.  
> 
> Is that related to the cause of the other patch from you, i.e.
> wanting to get "registers" but unable to?  If they manage to get the
> value of the register that holds 'key', would this disappear, I
> wonder?

I don't think so. t1300 fails consistently for me with -O2, and it doesn't have the "register" message (and never came up as one of the racy losers). I think the "register" thing is mostly just a harmless warning that doesn't change the output, but simply confuses our "did lsan produce any logs" check.

-Peff