linux-kernel - Re: [PATCH v3 0/2] Stop some of the abuse of BUG() where compile time checks should be used.

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]

Message-ID: <4ED3BED8.4000000@caviumnetworks.com>
Date:	Mon, 28 Nov 2011 09:03:20 -0800
From:	David Daney <ddaney@...iumnetworks.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	David Howells <dhowells@...hat.com>,
	David Daney <ddaney.cavm@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"ralf@...ux-mips.org" <ralf@...ux-mips.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arch@...r.kernel.org" <linux-arch@...r.kernel.org>,
	David Rientjes <rientjes@...gle.com>, DM <dm.n9107@...il.com>,
	David Daney <david.daney@...ium.com>,
	"Pinski, Andrew" <Andrew.Pinski@...iumnetworks.com>
Subject: Re: [PATCH v3 0/2] Stop some of the abuse of BUG() where compile
 time checks should be used.

On 11/24/2011 10:31 AM, Linus Torvalds wrote:
> On Thu, Nov 24, 2011 at 2:24 AM, David Howells<dhowells@...hat.com>  wrote:
>>
>> Have you tried asking the gcc folks if this is likely to get fixed soon?
>
> I actually don't think it's a bug. The error message is associated
> with the function declaration symbol, so it actually makes sense that
> there can be only one error message per callee - not per caller.
>

Yes, that is correct.

> Using "__LINE__" to then create fairly unique symbols (modulo
> #include, of course) gets around it in a pretty natural way as ddaney
> said, so if we care enough.  I don't think it's a big issue (as
> mentioned, I'd worry more about us making sure it's reliable enough to
> be used - we've had gcc sometimes fail to compile things out just
> because some optimization was not working well enough).
>

Since these are *build* bugs, they are of a different nature than the 
*runtime* variety.  They will never be seen at random times by someone 
running the kernel, so making it easier to determine their cause is less 
important.  Really, I would expect it to never really be an issue.

We will always know which file is the culprit.  Finding the line number 
can be done like this:

objdump -r $file | grep build_bug | addr2line -e $file

David Daney
--
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/