From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753386AbdJHKnp (ORCPT ); Sun, 8 Oct 2017 06:43:45 -0400 Received: from mail.sigma-star.at ([95.130.255.111]:45996 "EHLO mail.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751597AbdJHKno (ORCPT ); Sun, 8 Oct 2017 06:43:44 -0400 From: Richard Weinberger To: Thomas Meyer Cc: user-mode-linux-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: [PATCH] um: Fix kcov crash before kernel is started. Date: Sun, 08 Oct 2017 12:44:12 +0200 Message-ID: <2201510.o3ITaGZhUC@blindfold> In-Reply-To: <20171008103158.14107-1-thomas@m3y3r.de> References: <20171008103158.14107-1-thomas@m3y3r.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Sonntag, 8. Oktober 2017, 12:31:58 CEST schrieb Thomas Meyer: > UMLs current_thread_info() unconditionally assumes that the top of the stack > contains the thread_info structure. But on UML the __sanitizer_cov_trace_pc > function is called for *all* functions! This results in an early crash: > > Prevent kcov from using invalid curent_thread_info() data by checking > the system_state. > > Signed-off-by: Thomas Meyer > --- > kernel/kcov.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/kernel/kcov.c b/kernel/kcov.c > index 3f693a0f6f3e..d601c0e956f6 100644 > --- a/kernel/kcov.c > +++ b/kernel/kcov.c > @@ -56,6 +56,12 @@ void notrace __sanitizer_cov_trace_pc(void) > struct task_struct *t; > enum kcov_mode mode; > > +#ifdef CONFIG_UML > + if(!(system_state == SYSTEM_SCHEDULING || > + system_state == SYSTEM_RUNNING)) > + return; > +#endif Hmm, and why does it work on all other archs then? Thanks, //richard