linux-kernel - [PATCH -tip/perf/core] perf, x86: P4 PMU

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-next>] [day] [month] [year] [list]

Message-ID: <20110706172454.GJ5485@sun>
Date:	Wed, 6 Jul 2011 21:24:55 +0400
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Steven Rostedt <rostedt@...dmis.org>
Cc:	Don Zickus <dzickus@...hat.com>,
	Stephane Eranian <eranian@...gle.com>,
	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH -tip/perf/core] perf, x86: P4 PMU - Drop redundant
 WARN_ON_ONCE

This WARN_ON_ONCE triggers a false alarm on SMP because
nmi-watchdog uses a single global 'wd_hw_attr' variable
to serve perf event attributes and once p4_hw_watchdog_set_attr
has modified it subsequent calls on the rest cpus trigger
the warning.

It is safe to simply drop it since we know the caller may
pass already altered type and config.

Repoted-by: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Cyrill Gorcunov <gorcunov@...nvz.org>
---
 arch/x86/kernel/cpu/perf_event_p4.c |    3 ---
 1 file changed, 3 deletions(-)

Index: linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/cpu/perf_event_p4.c
+++ linux-2.6.git/arch/x86/kernel/cpu/perf_event_p4.c
@@ -726,9 +726,6 @@ static void p4_hw_watchdog_set_attr(stru
 	 * that named "non-sleeping" ticks as recommended
 	 * by Intel SDM Vol3b.
 	 */
-	WARN_ON_ONCE(wd_attr->type	!= PERF_TYPE_HARDWARE ||
-		     wd_attr->config	!= PERF_COUNT_HW_CPU_CYCLES);
-
 	wd_attr->type	= PERF_TYPE_RAW;
 	wd_attr->config	=
 		p4_config_pack_escr(P4_ESCR_EVENT(P4_EVENT_EXECUTION_EVENT)		|
--
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/