From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:34862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753748AbdHXOW0 (ORCPT ); Thu, 24 Aug 2017 10:22:26 -0400 Message-Id: <20170824142224.819431070@goodmis.org> Date: Thu, 24 Aug 2017 10:21:44 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Ingo Molnar , Andrew Morton , Tom Zanussi , stable@vger.kernel.org, Zamir SUN Subject: [PATCH 1/6] tracing: Call clear_boot_tracer() at lateinit_sync References: <20170824142143.110862355@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0001-tracing-Call-clear_boot_tracer-at-lateinit_sync.patch Sender: stable-owner@vger.kernel.org List-ID: From: "Steven Rostedt (VMware)" The clear_boot_tracer function is used to reset the default_bootup_tracer string to prevent it from being accessed after boot, as it originally points to init data. But since clear_boot_tracer() is called via the init_lateinit() call, it races with the initcall for registering the hwlat tracer. If someone adds "ftrace=hwlat" to the kernel command line, depending on how the linker sets up the text, the saved command line may be cleared, and the hwlat tracer never is initialized. Simply have the clear_boot_tracer() be called by initcall_lateinit_sync() as that's for tasks to be called after lateinit. Link: https://bugzilla.kernel.org/show_bug.cgi?id=196551 Cc: stable@vger.kernel.org Fixes: e7c15cd8a ("tracing: Added hardware latency tracer") Reported-by: Zamir SUN Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 42b9355033d4..784fb43b2abe 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8407,4 +8407,4 @@ __init static int clear_boot_tracer(void) } fs_initcall(tracer_init_tracefs); -late_initcall(clear_boot_tracer); +late_initcall_sync(clear_boot_tracer); -- 2.13.2