From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757600Ab2IDSxa (ORCPT ); Tue, 4 Sep 2012 14:53:30 -0400 Received: from terminus.zytor.com ([198.137.202.10]:47973 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752216Ab2IDSx2 (ORCPT ); Tue, 4 Sep 2012 14:53:28 -0400 Date: Tue, 4 Sep 2012 11:53:11 -0700 From: "tip-bot for K.Prasad" Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, a.p.zijlstra@chello.nl, Prasad.Krishnan@gmail.com, emachado@linux.vnet.ibm.com, fweisbec@gmail.com, naveen.n.rao@linux.vnet.ibm.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, Prasad.Krishnan@gmail.com, emachado@linux.vnet.ibm.com, fweisbec@gmail.com, naveen.n.rao@linux.vnet.ibm.com, tglx@linutronix.de In-Reply-To: <20120802081635.5811.17737.stgit@localhost.localdomain> References: <20120802081635.5811.17737.stgit@localhost.localdomain> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf/hwpb: Invoke __perf_event_disable() if interrupts are already disabled Git-Commit-ID: 500ad2d8b01390c98bc6dce068bccfa9534b8212 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.6 (terminus.zytor.com [127.0.0.1]); Tue, 04 Sep 2012 11:53:17 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 500ad2d8b01390c98bc6dce068bccfa9534b8212 Gitweb: http://git.kernel.org/tip/500ad2d8b01390c98bc6dce068bccfa9534b8212 Author: K.Prasad AuthorDate: Thu, 2 Aug 2012 13:46:35 +0530 Committer: Ingo Molnar CommitDate: Tue, 4 Sep 2012 17:29:53 +0200 perf/hwpb: Invoke __perf_event_disable() if interrupts are already disabled While debugging a warning message on PowerPC while using hardware breakpoints, it was discovered that when perf_event_disable is invoked through hw_breakpoint_handler function with interrupts disabled, a subsequent IPI in the code path would trigger a WARN_ON_ONCE message in smp_call_function_single function. This patch calls __perf_event_disable() when interrupts are already disabled, instead of perf_event_disable(). Reported-by: Edjunior Barbosa Machado Signed-off-by: K.Prasad [naveen.n.rao@linux.vnet.ibm.com: v3: Check to make sure we target current task] Signed-off-by: Naveen N. Rao Acked-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120802081635.5811.17737.stgit@localhost.localdomain [ Fixed build error on MIPS. ] Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 2 ++ kernel/events/core.c | 2 +- kernel/events/hw_breakpoint.c | 11 ++++++++++- 3 files changed, 13 insertions(+), 2 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index ad04dfc..33ed9d6 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -1296,6 +1296,7 @@ extern int perf_swevent_get_recursion_context(void); extern void perf_swevent_put_recursion_context(int rctx); extern void perf_event_enable(struct perf_event *event); extern void perf_event_disable(struct perf_event *event); +extern int __perf_event_disable(void *info); extern void perf_event_task_tick(void); #else static inline void @@ -1334,6 +1335,7 @@ static inline int perf_swevent_get_recursion_context(void) { return -1; } static inline void perf_swevent_put_recursion_context(int rctx) { } static inline void perf_event_enable(struct perf_event *event) { } static inline void perf_event_disable(struct perf_event *event) { } +static inline int __perf_event_disable(void *info) { return -1; } static inline void perf_event_task_tick(void) { } #endif diff --git a/kernel/events/core.c b/kernel/events/core.c index efef428..7fee567 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -1253,7 +1253,7 @@ retry: /* * Cross CPU call to disable a performance event */ -static int __perf_event_disable(void *info) +int __perf_event_disable(void *info) { struct perf_event *event = info; struct perf_event_context *ctx = event->ctx; diff --git a/kernel/events/hw_breakpoint.c b/kernel/events/hw_breakpoint.c index bb38c4d..9a7b487 100644 --- a/kernel/events/hw_breakpoint.c +++ b/kernel/events/hw_breakpoint.c @@ -453,7 +453,16 @@ int modify_user_hw_breakpoint(struct perf_event *bp, struct perf_event_attr *att int old_type = bp->attr.bp_type; int err = 0; - perf_event_disable(bp); + /* + * modify_user_hw_breakpoint can be invoked with IRQs disabled and hence it + * will not be possible to raise IPIs that invoke __perf_event_disable. + * So call the function directly after making sure we are targeting the + * current task. + */ + if (irqs_disabled() && bp->ctx && bp->ctx->task == current) + __perf_event_disable(bp); + else + perf_event_disable(bp); bp->attr.bp_addr = attr->bp_addr; bp->attr.bp_type = attr->bp_type;