From: Stephane Eranian Date: Wed, 8 Jan 2014 10:15:52 +0000 (+0100) Subject: perf/x86: Fix active_entry initialization X-Git-Tag: v3.14-rc1~171^2~7 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=f3ae75de98c4bac145a87d830c156c96f9414022;p=platform%2Fkernel%2Flinux-stable.git perf/x86: Fix active_entry initialization 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 Cc: ak@linux.intel.com Cc: acme@redhat.com Cc: jolsa@redhat.com Cc: zheng.z.yan@intel.com Cc: bp@alien8.de Cc: vincent.weaver@maine.edu Cc: maria.n.dimakopoulou@gmail.com Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1389176153-3128-2-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar --- 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 89d34f9..c3b6c27 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6670,6 +6670,8 @@ 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);