linux-kernel - Re: [PATCH 2/3] perf: Move exclude_kernel tracepoint check to init event

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] [day] [month] [year] [list]

Message-ID: <20151126204428.GL28162@kernel.org>
Date:	Thu, 26 Nov 2015 17:44:28 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Jiri Olsa <jolsa@...hat.com>
Cc:	Jiri Olsa <jolsa@...nel.org>, Steven Rostedt <rostedt@...dmis.org>,
	lkml <linux-kernel@...r.kernel.org>,
	David Ahern <dsahern@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH 2/3] perf: Move exclude_kernel tracepoint check to init
 event

Em Thu, Nov 26, 2015 at 08:49:10PM +0100, Jiri Olsa escreveu:
> On Thu, Nov 26, 2015 at 04:41:06PM -0300, Arnaldo Carvalho de Melo wrote:
> > Em Thu, Nov 26, 2015 at 08:34:48PM +0100, Jiri Olsa escreveu:
> > > We suppress events with attr::exclude_kernel set when
> > > the event is generated, so following capture will
> > > give no warning and produce no data:
> > > 
> > >   $ sudo perf record -e sched:sched_switch:u ls
> > >   $ sudo /perf script | wc -l
> > >   0
> > > 
> > > Checking the attr::exclude_kernel at the event init
> > > time and failing right away:
> > 
> > We can as well provide a better warning in the tooling side and don't
> > even ask this nonsensical combo to the kernel, right?
> 
> yep.. I'll update my todo ;-)

Thanks!
 
> > Arguably the kernel was doing what was asked for, its just that no
> > sched:sched_switch took place while in user space... ;-)
> 
> I think it's better to fail like that.. rather than spending
> time on figuring why my test did not give me any data ;-)

Up to peterz ;-)

- Arnaldo
--
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/