linux-kernel - Re: [PATCH] perf_events: fix bogus warn_on(_once) in perf_prepare

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: <1270761341.20295.3160.camel@laptop>
Date:	Thu, 08 Apr 2010 23:15:41 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	linux-kernel@...r.kernel.org, mingo@...e.hu, paulus@...ba.org,
	davem@...emloft.net, fweisbec@...il.com, robert.richter@....com,
	perfmon2-devel@...ts.sf.net, eranian@...il.com
Subject: Re: [PATCH] perf_events: fix bogus warn_on(_once) in 
 perf_prepare_sample()

On Thu, 2010-04-08 at 23:08 +0200, Stephane Eranian wrote:
> On Thu, Apr 8, 2010 at 10:55 PM, Peter Zijlstra <peterz@...radead.org> wrote:
> > On Thu, 2010-04-08 at 22:45 +0200, Stephane Eranian wrote:
> >>       There is a warn_on_once() check for PERF_SAMPLE_RAW which trips
> >>       when using PEBS on both Core and Nehalem. Core PEBS sample size is 144
> >>       bytes and 176 bytes for Nehalem. Both are multiples of 8, but the size
> >>       field is encoded as int, thus the total is never a multiple of 8 which
> >>       trips the check. I think the size should have been u64, but now it is
> >>       too late to change given it is ABI.
> >
> > PEBS hasn't seen -linus yet, so we can fix that.
> >
> Are you suggesting you add some padding the PEBS raw sample you
> return as PERF_SAMPLE_RAW? Then you need to define what RAW
> actually means? Seems here, it would mean more than what the
> HW returns. 

The best fix here is to simply remove the PERF_SAMPLE_RAW support and
implement PERF_SAMPLE_REGS. Its just that we need to come up with a way
to deal with compat pt_regs muck.



--
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/