From: Ingo Molnar <mingo@kernel.org>
To: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Sam Ravnborg <sam@ravnborg.org>,
lkml <linux-kernel@vger.kernel.org>, Michael Matz <matz@suse.de>,
linux-kbuild@vger.kernel.org, x86-ml <x86@kernel.org>,
Arnaldo Carvalho de Melo <acme@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] Kbuild: Move -Wmaybe-uninitialized to W=1
Date: Thu, 28 Jul 2016 19:04:13 +0200 [thread overview]
Message-ID: <20160728170413.GA15229@gmail.com> (raw)
In-Reply-To: <20160728164956.GA2865@gmail.com>
* Ingo Molnar <mingo@kernel.org> wrote:
> But that's my point, I believe the false positive rate is pretty low in fact, due
> to three factors:
>
> - 90% of the warnings get fixed by developers, we never see them upstream
>
> - I'd say a majority (say 70%) of the remaining warnings are flagging 'complexity
> bugs'
>
> - only a residual 3% are obnoxious ones.
>
> But these remaining 3% are the ones we are seeing again and again in various
> compiler output, so we tend to get a subjective impression that this warning
> produces countless false positives.
And note that I am well aware of the real risk this poses: people will ignore real
warnings if there are so many residual false positives.
I think this approach worked pretty well for perf:
> So I *think* the better option would be to do what we are doing in the perf
> tooling: force a build error for these warnings (by default, with an option
> available to make it build). That flushes them out and also makes it sure that
> those questionable sequences of code never get upstream to begin with.
... but might not be appropriate for the kernel which is a 2 orders of magnitude
larger code base.
Thanks,
Ingo
next prev parent reply other threads:[~2016-07-28 17:04 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-16 13:20 [RFC] Turn off -Wmaybe-uninitialized completely and move it to W=1 Borislav Petkov
2014-06-16 21:14 ` Sam Ravnborg
2014-06-24 21:38 ` [PATCH] Kbuild: Move -Wmaybe-uninitialized " Borislav Petkov
2014-07-07 10:53 ` Borislav Petkov
2014-07-08 9:25 ` Paul Bolle
2014-07-08 11:37 ` Borislav Petkov
2014-07-10 10:42 ` Borislav Petkov
2014-07-10 11:03 ` Paul Bolle
2016-07-28 4:20 ` Borislav Petkov
2016-07-28 8:29 ` Ingo Molnar
2016-07-28 8:46 ` Borislav Petkov
2016-07-28 16:49 ` Ingo Molnar
2016-07-28 17:04 ` Ingo Molnar [this message]
2016-07-28 17:56 ` Markus Trippelsdorf
2016-07-28 19:03 ` Linus Torvalds
2016-07-28 19:08 ` Linus Torvalds
2016-07-28 20:28 ` Ingo Molnar
2016-07-28 21:22 ` Linus Torvalds
2016-07-29 10:08 ` Arnd Bergmann
2016-07-29 10:19 ` Borislav Petkov
2016-07-29 10:35 ` Arnd Bergmann
2016-07-29 18:26 ` Linus Torvalds
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