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_HELO_NONE,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 07871C04AB4 for ; Fri, 17 May 2019 18:51:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CD6A121734 for ; Fri, 17 May 2019 18:51:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728473AbfEQSvl (ORCPT ); Fri, 17 May 2019 14:51:41 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43834 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726732AbfEQSvk (ORCPT ); Fri, 17 May 2019 14:51:40 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 26FB8C09AD16; Fri, 17 May 2019 18:51:40 +0000 (UTC) Received: from jlaw-desktop.bos.redhat.com (dhcp-17-208.bos.redhat.com [10.18.17.208]) by smtp.corp.redhat.com (Postfix) with ESMTP id 28DBC413C; Fri, 17 May 2019 18:51:35 +0000 (UTC) From: Joe Lawrence To: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org Cc: jikos@kernel.org, joe.lawrence@redhat.com, jpoimboe@redhat.com, pmladek@suse.com, tglx@linutronix.de Subject: [PATCH] stacktrace: fix CONFIG_ARCH_STACKWALK stack_trace_save_tsk_reliable return Date: Fri, 17 May 2019 14:51:17 -0400 Message-Id: <20190517185117.24642-1-joe.lawrence@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 17 May 2019 18:51:40 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Miroslav reported that the livepatch self-tests were failing, specifically a case in which the consistency model ensures that we do not patch a current executing function, "TEST: busy target module". Recent renovations to stack_trace_save_tsk_reliable() left it returning only an -ERRNO success indication in some configuration combinations: klp_check_stack() ret = stack_trace_save_tsk_reliable() #ifdef CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE stack_trace_save_tsk_reliable() ret = arch_stack_walk_reliable() return 0 return -EINVAL ... return ret; ... if (ret < 0) /* stack_trace_save_tsk_reliable error */ nr_entries = ret; << 0 Previously (and currently for !CONFIG_ARCH_STACKWALK && CONFIG_HAVE_RELIABLE_STACKTRACE) stack_trace_save_tsk_reliable() returned the number of entries that it consumed in the passed storage array. In the case of the above config and trace, be sure to return the stacktrace_cookie.len on stack_trace_save_tsk_reliable() success. Fixes: 25e39e32b0a3f ("livepatch: Simplify stack trace retrieval") Reported-by: Miroslav Benes Signed-off-by: Joe Lawrence --- kernel/stacktrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index 27bafc1e271e..90d3e0bf0302 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -206,7 +206,7 @@ int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store, ret = arch_stack_walk_reliable(consume_entry, &c, tsk); put_task_stack(tsk); - return ret; + return ret ? ret : c.len; } #endif -- 2.20.1