linux-kernel - Re: [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 06 Aug 2014 11:23:47 +0100
From:	Måns Rullgård <mans@...sr.com>
To:	Jakub Jelinek <jakub@...hat.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	"Frank Ch. Eigler" <fche@...hat.com>,
	Josh Boyer <jwboyer@...oraproject.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	stable <stable@...r.kernel.org>,
	Michel Dänzer <michel@...nzer.net>,
	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Josh Stone <jistone@...hat.com>
Subject: Re: [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler

Jakub Jelinek <jakub@...hat.com> writes:

> There have been several man-years of work to get from the 25% var coverage
> to 67%, several DWARF extensions (most of them to be available in DWARF5 or
> work in progress on that) and with -fno-var-tracking-assignments that is
> just returned to the old state.

This is a typical "but look at all the work we've put in, it *has* to
work" argument.  As always, it is completely without merit.

>> In other words, anybody who relies on it has already learnt to work
>> around it. Or, more likely, there just isn't anybody who relies on it.
>> 
>> I don't understand how you guys can be so cavalier about a compiler
>> bug that has already resulted in actual real problems. You bring up
>
> I have no problem with a -fno-var-tracking-assignments workaround for
> compilers that have the PR61801 wrong-code bug.

Are there any that with reasonable confidence do not?

-- 
Måns Rullgård
mans@...sr.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/