From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933724Ab3GPTC2 (ORCPT ); Tue, 16 Jul 2013 15:02:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49894 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754929Ab3GPTC1 (ORCPT ); Tue, 16 Jul 2013 15:02:27 -0400 Date: Tue, 16 Jul 2013 20:57:20 +0200 From: Oleg Nesterov To: Steven Rostedt , Masami Hiramatsu Cc: "zhangwei(Jovi)" , Jiri Olsa , Peter Zijlstra , Arnaldo Carvalho de Melo , Srikar Dronamraju , Frederic Weisbecker , Ingo Molnar , Andrew Morton , linux-kernel@vger.kernel.org Subject: [RFC PATCH 1/4] tracing: Change remove_event_from_tracers() to clear d_subdirs->i_private Message-ID: <20130716185720.GA21189@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130716185658.GA21167@redhat.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Preparation to make the next patches more understandable. The caller of trace_remove_event_call() is going to free call/files, this means that every opened id/filter/enable/format file will use the already freed memory via filp->private_data / inode->i_private. Change remove_event_from_tracers() to clear ->i_private for every child. This fixes nothing and even makes the crash more possible, but this allows to fix the problem later. Note: this doesn't affect instance_rmdir() paths. It has the similar problems and they will be fixed separately. Signed-off-by: Oleg Nesterov --- kernel/trace/trace_events.c | 9 +++++++++ 1 files changed, 9 insertions(+), 0 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 9d2b499..cbd1a57 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1534,6 +1534,14 @@ static void remove_subsystem(struct ftrace_subsystem_dir *dir) } } +static void invalidate_event_file(struct dentry *dir) +{ + struct dentry *child; + /* ->i_mutex is not needed, nodody can create/remove a file */ + list_for_each_entry(child, &dir->d_subdirs, d_u.d_child) + child->d_inode->i_private = NULL; +} + static void remove_event_from_tracers(struct ftrace_event_call *call) { struct ftrace_event_file *file; @@ -1545,6 +1553,7 @@ static void remove_event_from_tracers(struct ftrace_event_call *call) continue; list_del(&file->list); + invalidate_event_file(file->dir); debugfs_remove_recursive(file->dir); remove_subsystem(file->system); kmem_cache_free(file_cachep, file); -- 1.5.5.1