From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753374AbdJHKcu (ORCPT ); Sun, 8 Oct 2017 06:32:50 -0400 Received: from www17.your-server.de ([213.133.104.17]:39121 "EHLO www17.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751523AbdJHKct (ORCPT ); Sun, 8 Oct 2017 06:32:49 -0400 From: Thomas Meyer To: user-mode-linux-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, richard@nod.at Cc: Thomas Meyer Subject: [PATCH] um: Fix kcov crash before kernel is started. Date: Sun, 8 Oct 2017 12:31:58 +0200 Message-Id: <20171008103158.14107-1-thomas@m3y3r.de> X-Mailer: git-send-email 2.11.0 X-Authenticated-Sender: thomas@m3y3r.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 + t = current; /* * We are interested in code coverage as a function of a syscall inputs, -- 2.11.0