linux-kernel - Re: [GIT PULL] perf fixes

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20131001084247.GE21793@gmail.com>
Date:	Tue, 1 Oct 2013 10:42:47 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Andi Kleen <ak@...ux.intel.com>
Cc:	Markus Trippelsdorf <markus@...ppelsdorf.de>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	linux-kernel@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...radead.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: Re: [GIT PULL] perf fixes


* Andi Kleen <ak@...ux.intel.com> wrote:

> > > Hmm, works for me. In fact I wrote it to fix a perf top issue.
> >
> > What 'issue' and why wasn't it described in the changelog more 
> > accurately?
> >
> > The blurb you wrote in the changelog:
> > 
> > | The libbfd C++ demangler doesn't seem to deal with cloned functions, 
> > | like symbol.clone.NUM.
> > |
> > | Just strip the dot part before demangling and add it back later.
> > 
> > Only alludes to a C++ symbol resolution annoyance and thus isn't very 
> > informative.
> 
> The issue was that I saw a long unreadable line noise string in 
> report/top, instead of a demangled function. After I stripped the 
> postfix I got the demangled symbol as expected.

We obviously don't want to trade output annoyances for crashes, nor does 
it justify the code uglies you introduced with the patch - which made the 
code obviously unrobust.

My guess would be that maybe it's the cast of a const pointer that 
possibly broke GCC's aliasing detection on Markus's system or so. But 
maybe there's a more direct bug in the code as well, the code you added is 
too ugly to be reviewed efficiently, please send a cleaned up version.

Thanks,

	Ingo
--
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/