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=-6.8 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 E52CDC35240 for ; Thu, 30 Jan 2020 14:49:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BBD8C206F0 for ; Thu, 30 Jan 2020 14:49:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727647AbgA3OtQ (ORCPT ); Thu, 30 Jan 2020 09:49:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:33558 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727328AbgA3OsM (ORCPT ); Thu, 30 Jan 2020 09:48:12 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (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 2604B24686; Thu, 30 Jan 2020 14:48:12 +0000 (UTC) Received: from rostedt by gandalf.local.home with local (Exim 4.93) (envelope-from ) id 1ixB75-001CM8-34; Thu, 30 Jan 2020 09:48:11 -0500 Message-Id: <20200130144810.971745670@goodmis.org> User-Agent: quilt/0.65 Date: Thu, 30 Jan 2020 09:47:48 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Ingo Molnar , Andrew Morton , Vasily Averin Subject: [for-next][PATCH 05/21] tracing: eval_map_next() should always increase position index References: <20200130144743.527378179@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: Vasily Averin if seq_file .next fuction does not change position index, read after some lseek can generate unexpected output. Link: http://lkml.kernel.org/r/7ad85b22-1866-977c-db17-88ac438bc764@virtuozzo.com Signed-off-by: Vasily Averin [ This is not a bug fix, it just makes it "technically correct" which is why I applied it. NULL is only returned on an anomaly which triggers a WARN_ON ] Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6a28b1b9bf42..8d144fd94aa8 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5399,14 +5399,12 @@ static void *eval_map_next(struct seq_file *m, void *v, loff_t *pos) * Paranoid! If ptr points to end, we don't want to increment past it. * This really should never happen. */ + (*pos)++; ptr = update_eval_map(ptr); if (WARN_ON_ONCE(!ptr)) return NULL; ptr++; - - (*pos)++; - ptr = update_eval_map(ptr); return ptr; -- 2.24.1