Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759614Ab0GAWFj (ORCPT ); Thu, 1 Jul 2010 18:05:39 -0400 Received: from kroah.org ([198.145.64.141]:33673 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758725Ab0GAVMn (ORCPT ); Thu, 1 Jul 2010 17:12:43 -0400 X-Mailbox-Line: From gregkh@clark.site Thu Jul 1 10:42:46 2010 Message-Id: <20100701174246.785204764@clark.site> User-Agent: quilt/0.48-10.1 Date: Thu, 01 Jul 2010 10:41:34 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Peter Zijlstra , Arnaldo Carvalho de Melo , Frederic Weisbecker , Paul Mackerras , Ingo Molnar Subject: [004/200] perf: Fix exit() vs PERF_FORMAT_GROUP In-Reply-To: <20100701175201.GA2149@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2642 Lines: 83 2.6.34-stable review patch. If anyone has any objections, please let me know. ------------------ From: Peter Zijlstra commit 050735b08ca8a016bbace4445fa025b88fee770b upstream. Both Stephane and Corey reported that PERF_FORMAT_GROUP didn't work as expected if the task the counters were attached to quit before the read() call. The cause is that we unconditionally destroy the grouping when we remove counters from their context. Fix this by splitting off the group destroy from the list removal such that perf_event_remove_from_context() does not do this and change perf_event_release() to do so. Reported-by: Corey Ashford Reported-by: Stephane Eranian Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Paul Mackerras LKML-Reference: <1273571513.5605.3527.camel@twins> Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/perf_event.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -315,8 +315,6 @@ list_add_event(struct perf_event *event, static void list_del_event(struct perf_event *event, struct perf_event_context *ctx) { - struct perf_event *sibling, *tmp; - if (list_empty(&event->group_entry)) return; ctx->nr_events--; @@ -340,6 +338,12 @@ list_del_event(struct perf_event *event, */ if (event->state > PERF_EVENT_STATE_OFF) event->state = PERF_EVENT_STATE_OFF; +} + +static void +perf_destroy_group(struct perf_event *event, struct perf_event_context *ctx) +{ + struct perf_event *sibling, *tmp; /* * If this was a group event with sibling events then @@ -1856,9 +1860,18 @@ int perf_event_release_kernel(struct per { struct perf_event_context *ctx = event->ctx; + /* + * Remove from the PMU, can't get re-enabled since we got + * here because the last ref went. + */ + perf_event_disable(event); + WARN_ON_ONCE(ctx->parent_ctx); mutex_lock(&ctx->mutex); - perf_event_remove_from_context(event); + raw_spin_lock_irq(&ctx->lock); + list_del_event(event, ctx); + perf_destroy_group(event, ctx); + raw_spin_unlock_irq(&ctx->lock); mutex_unlock(&ctx->mutex); mutex_lock(&event->owner->perf_event_mutex); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/