linux-kernel - Re: [PATCH 1/2] perf: Add persistent event facilities

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:	Fri, 18 May 2012 12:49:47 +0200
From:	Borislav Petkov <bp@...64.org>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Borislav Petkov <bp@...64.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...e.hu>,
	Steven Rostedt <rostedt@...dmis.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/2] perf: Add persistent event facilities

On Fri, May 18, 2012 at 12:09:13PM +0200, Peter Zijlstra wrote:
> On Wed, 2012-03-21 at 15:34 +0100, Borislav Petkov wrote:
> > +                               persistent     :  1, /* always-on event */
> 
> Should creating something like that be privileged?

Yeah, I dunno, do we want that? Well, what it is when we enable an event
during boot, i.e. say "boot_trace=<event>..." on the kernel command line
and this event is enabled until we finish booting. Then we disable it
with perf or over debugfs. Is that privileged or can any user boot-trace
the system?

All good questions.

> And it looks like you allow creating persistent per-task events; is
> that useful, if so why? And like already pointed out, your cleanup
> seems broken in that case.

This was dumb - I wanted to have task-agnostic events which get enabled
for the whole system and there's a buffer on each CPU which collects
their output. It was a first attempt and it is a good thing you gave it
a look so that I can address the issues properly.

Thanks.

-- 
Regards/Gruss,
Boris.

Advanced Micro Devices GmbH
Einsteinring 24, 85609 Dornach
GM: Alberto Bozzo
Reg: Dornach, Landkreis Muenchen
HRB Nr. 43632 WEEE Registernr: 129 19551
--
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/