From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B488C43387 for ; Fri, 21 Dec 2018 17:56:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7438C21927 for ; Fri, 21 Dec 2018 17:56:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391134AbeLUR45 (ORCPT ); Fri, 21 Dec 2018 12:56:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:55826 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388512AbeLUR45 (ORCPT ); Fri, 21 Dec 2018 12:56:57 -0500 Received: from gandalf.local.home (cpe-66-24-56-78.stny.res.rr.com [66.24.56.78]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9454D21939; Fri, 21 Dec 2018 17:56:56 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.91) (envelope-from ) id 1gaP2d-0002HW-Md; Fri, 21 Dec 2018 12:56:55 -0500 Message-Id: <20181221175655.579715713@goodmis.org> User-Agent: quilt/0.65 Date: Fri, 21 Dec 2018 12:56:20 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Namhyung Kim , Masami Hiramatsu , Will Deacon , Anders Roxell Subject: [for-next][PATCH 02/24] arm64: ftrace: Set FTRACE_MAY_SLEEP before ftrace_modify_all_code() References: <20181221175618.968519903@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Steven Rostedt (VMware)" It has been reported that ftrace_replace_code() which is called by ftrace_modify_all_code() can cause a soft lockup warning for an allmodconfig kernel. This is because all the debug options enabled causes the loop in ftrace_replace_code() (which loops over all the functions being enabled where there can be 10s of thousands), is too slow, and never schedules out. To solve this, setting FTRACE_MAY_SLEEP to the command passed into ftrace_replace_code() will make it call cond_resched() in the loop, which prevents the soft lockup warning from triggering. Link: http://lkml.kernel.org/r/20181204192903.8193-1-anders.roxell@linaro.org Link: http://lkml.kernel.org/r/20181205183304.000714627@goodmis.org Acked-by: Will Deacon Reported-by: Anders Roxell Tested-by: Anders Roxell Signed-off-by: Steven Rostedt (VMware) --- arch/arm64/kernel/ftrace.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 57e962290df3..57d4e936a176 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -193,6 +193,7 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, void arch_ftrace_update_code(int command) { + command |= FTRACE_MAY_SLEEP; ftrace_modify_all_code(command); } -- 2.19.2