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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 E1F46C04EB8 for ; Fri, 30 Nov 2018 15:21:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A8D7D2146D for ; Fri, 30 Nov 2018 15:21:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A8D7D2146D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726824AbeLACao (ORCPT ); Fri, 30 Nov 2018 21:30:44 -0500 Received: from mail.kernel.org ([198.145.29.99]:50576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726127AbeLACao (ORCPT ); Fri, 30 Nov 2018 21:30:44 -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 9B40420868; Fri, 30 Nov 2018 15:21:03 +0000 (UTC) Date: Fri, 30 Nov 2018 10:21:02 -0500 From: Steven Rostedt To: Anders Roxell Cc: keescook@chromium.org, mingo@redhat.com, catalin.marinas@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Arnd Bergmann Subject: Re: [PATCH 1/3] stackleak: mark stackleak_track_stack() as notrace Message-ID: <20181130102102.041b8291@gandalf.local.home> In-Reply-To: <20181130150859.27366-1-anders.roxell@linaro.org> References: <20181130150859.27366-1-anders.roxell@linaro.org> X-Mailer: Claws Mail 3.16.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 Nov 2018 16:08:59 +0100 Anders Roxell wrote: > Function graph tracing recurses into itself when stackleak is enabled, > causing the ftrace graph selftest to run for up to 90 seconds and > trigger the softlockup watchdog. > > Breakpoint 2, ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200 > 200 mcount_get_lr_addr x0 // pointer to function's saved lr > (gdb) bt > \#0 ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:200 > \#1 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153 > \#2 0xffffff8008555484 in stackleak_track_stack () at ../kernel/stackleak.c:106 > \#3 0xffffff8008421ff8 in ftrace_ops_test (ops=0xffffff8009eaa840 , ip=18446743524091297036, regs=) at ../kernel/trace/ftrace.c:1507 > \#4 0xffffff8008428770 in __ftrace_ops_list_func (regs=, ignored=, parent_ip=, ip=) at ../kernel/trace/ftrace.c:6286 > \#5 ftrace_ops_no_ops (ip=18446743524091297036, parent_ip=18446743524091242824) at ../kernel/trace/ftrace.c:6321 > \#6 0xffffff80081d5280 in ftrace_caller () at ../arch/arm64/kernel/entry-ftrace.S:153 > \#7 0xffffff800832fd10 in irq_find_mapping (domain=0xffffffc03fc4bc80, hwirq=27) at ../kernel/irq/irqdomain.c:876 > \#8 0xffffff800832294c in __handle_domain_irq (domain=0xffffffc03fc4bc80, hwirq=27, lookup=true, regs=0xffffff800814b840) at ../kernel/irq/irqdesc.c:650 > \#9 0xffffff80081d52b4 in ftrace_graph_caller () at ../arch/arm64/kernel/entry-ftrace.S:205 > > Rework so we mark stackleak_track_stack as notrace > > Co-developed-by: Arnd Bergmann > Signed-off-by: Arnd Bergmann > Signed-off-by: Anders Roxell Acked-by: Steven Rostedt (VMware) -- Steve > --- > kernel/stackleak.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/stackleak.c b/kernel/stackleak.c > index e42892926244..5de3bf596dd7 100644 > --- a/kernel/stackleak.c > +++ b/kernel/stackleak.c > @@ -102,7 +102,7 @@ asmlinkage void stackleak_erase(void) > current->lowest_stack = current_top_of_stack() - THREAD_SIZE/64; > } > > -void __used stackleak_track_stack(void) > +void __used notrace stackleak_track_stack(void) > { > /* > * N.B. stackleak_erase() fills the kernel stack with the poison value,