Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755998AbaAHKQK (ORCPT ); Wed, 8 Jan 2014 05:16:10 -0500 Received: from mail-wi0-f182.google.com ([209.85.212.182]:37986 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755298AbaAHKQE (ORCPT ); Wed, 8 Jan 2014 05:16:04 -0500 From: Stephane Eranian To: linux-kernel@vger.kernel.org Cc: peterz@infradead.org, mingo@elte.hu, ak@linux.intel.com, acme@redhat.com, jolsa@redhat.com, zheng.z.yan@intel.com, bp@alien8.de, vincent.weaver@maine.edu, maria.n.dimakopoulou@gmail.com Subject: [PATCH v2 1/2] perf/x86: fix active_entry initialization Date: Wed, 8 Jan 2014 11:15:52 +0100 Message-Id: <1389176153-3128-2-git-send-email-eranian@google.com> X-Mailer: git-send-email 1.7.9.5 In-Reply-To: <1389176153-3128-1-git-send-email-eranian@google.com> References: <1389176153-3128-1-git-send-email-eranian@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch fixes a problem with the initialization of the struct perf_event active_entry field. It is defined inside an anonymous union and was initialized in perf_event_alloc() using INIT_LIST_HEAD(). However at that time, we do not know whether the event is going to use active_entry or hlist_entry (SW). Or at last, we don't want to make that determination there. The problem is that hlist and list_head are not initialized the same way. One is okay with NULL (from kzmalloc), the other needs to pointers to point to self. This patch resolves this problem by dropping the union. This will avoid problems later on, if someone starts using active_entry or hlist_entry without verifying that they actually overlap. This also solves the initialization problem. Signed-off-by: Stephane Eranian --- include/linux/perf_event.h | 6 ++---- kernel/events/core.c | 2 ++ 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 8f4a70f..e56b07f 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -319,10 +319,8 @@ struct perf_event { */ struct list_head migrate_entry; - union { - struct hlist_node hlist_entry; - struct list_head active_entry; - }; + struct hlist_node hlist_entry; + struct list_head active_entry; int nr_siblings; int group_flags; struct perf_event *group_leader; diff --git a/kernel/events/core.c b/kernel/events/core.c index 4b743b2..74fdef5 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6685,6 +6685,8 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, INIT_LIST_HEAD(&event->sibling_list); INIT_LIST_HEAD(&event->rb_entry); INIT_LIST_HEAD(&event->active_entry); + INIT_HLIST_NODE(&event->hlist_entry); + init_waitqueue_head(&event->waitq); init_irq_work(&event->pending, perf_pending_event); -- 1.7.9.5 -- 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/