From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758851AbZCWP6m (ORCPT ); Mon, 23 Mar 2009 11:58:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757786AbZCWP6b (ORCPT ); Mon, 23 Mar 2009 11:58:31 -0400 Received: from hera.kernel.org ([140.211.167.34]:48382 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757000AbZCWP6a (ORCPT ); Mon, 23 Mar 2009 11:58:30 -0400 Date: Mon, 23 Mar 2009 15:57:36 GMT From: Frederic Weisbecker To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, fweisbec@gmail.com, rostedt@goodmis.org, gregkh@suse.de, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, fweisbec@gmail.com, rostedt@goodmis.org, gregkh@suse.de, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1237759847-21025-3-git-send-email-fweisbec@gmail.com> References: <1237759847-21025-3-git-send-email-fweisbec@gmail.com> Subject: [tip:tracing/ftrace] tracing/ftrace: check if debugfs is registered before creating files Message-ID: Git-Commit-ID: 3e1f60b80cafcb5d7e8d3665b35962fbb8fb9efa X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Mon, 23 Mar 2009 15:57:38 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 3e1f60b80cafcb5d7e8d3665b35962fbb8fb9efa Gitweb: http://git.kernel.org/tip/3e1f60b80cafcb5d7e8d3665b35962fbb8fb9efa Author: Frederic Weisbecker AuthorDate: Sun, 22 Mar 2009 23:10:45 +0100 Committer: Ingo Molnar CommitDate: Mon, 23 Mar 2009 16:25:47 +0100 tracing/ftrace: check if debugfs is registered before creating files Impact: fix a crash with ftrace={nop,boot} parameter If the nop or initcall tracers are launched as boot tracers, they will attempt to create their option directory and files. But these tracers are registered very early and then assigned as "boot tracers" very early if asked to. Since they do this before debugfs has been registered (core initcall), a crash is triggered. Another early tracers could also come later. So we fix it by checking if debugfs is initialized before creating the root tracing directory. Signed-off-by: Frederic Weisbecker Cc: Greg Kroah-Hartman Cc: Steven Rostedt LKML-Reference: <1237759847-21025-3-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar --- kernel/trace/trace.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ace685c..f0e1337 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3513,6 +3513,9 @@ struct dentry *tracing_init_dentry(void) if (d_tracer) return d_tracer; + if (!debugfs_initialized()) + return NULL; + d_tracer = debugfs_create_dir("tracing", NULL); if (!d_tracer && !once) {