From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758413AbcBXRxJ (ORCPT ); Wed, 24 Feb 2016 12:53:09 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:55640 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753983AbcBXRxB (ORCPT ); Wed, 24 Feb 2016 12:53:01 -0500 Message-Id: <20160224174947.793996260@infradead.org> User-Agent: quilt/0.61-1 Date: Wed, 24 Feb 2016 18:45:42 +0100 From: Peter Zijlstra To: peterz@infradead.org, mingo@kernel.org, alexander.shishkin@linux.intel.com, eranian@google.com Cc: linux-kernel@vger.kernel.org, vince@deater.net, dvyukov@google.com, andi@firstfloor.org, jolsa@redhat.com, panand@redhat.com, sasha.levin@oracle.com, oleg@redhat.com Subject: [PATCH 03/12] perf: Allow perf_release() with !event->ctx References: <20160224174539.570749654@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-perf-more-fixes-3.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In the err_file: fput(event_file) case, the event will not yet have been attached to a context. However perf_release() does assume it has been. Cure this. Reviewed-by: Alexander Shishkin Tested-by: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3754,9 +3754,19 @@ static void put_event(struct perf_event */ int perf_event_release_kernel(struct perf_event *event) { - struct perf_event_context *ctx; + struct perf_event_context *ctx = event->ctx; struct perf_event *child, *tmp; + /* + * If we got here through err_file: fput(event_file); we will not have + * attached to a context yet. + */ + if (!ctx) { + WARN_ON_ONCE(event->attach_state & + (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP)); + goto no_ctx; + } + if (!is_kernel_event(event)) perf_remove_from_owner(event); @@ -3832,8 +3842,8 @@ int perf_event_release_kernel(struct per } mutex_unlock(&event->child_mutex); - /* Must be the last reference */ - put_event(event); +no_ctx: + put_event(event); /* Must be the 'last' reference */ return 0; } EXPORT_SYMBOL_GPL(perf_event_release_kernel);