linux-kernel - Re: [BUG] perf_event: when events are grouped, the time enabled / running values are incorrect

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: <1273608676.1810.61.camel@laptop>
Date:	Tue, 11 May 2010 22:11:16 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	eranian@...il.com
Cc:	Corey Ashford <cjashfor@...ux.vnet.ibm.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Paul Mackerras <paulus@...ba.org>, eranian@...gle.com
Subject: Re: [BUG] perf_event: when events are grouped, the time enabled / 
 running values are incorrect

On Tue, 2010-05-11 at 21:55 +0200, stephane eranian wrote:
> Events are also grouped in this example. Both this same issue exists
> also when only
> one event is used. I suspect an update_event_times() or
> update_group_times() is also
> missing on the sampling path in perf_overflow_handler().

Hrmm, you're right, except fixing that is non-trivial.
update_event_times() wants to be called with ctx->lock held and we can't
do that from NMI context.

--
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/