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=-6.3 required=3.0 tests=BAYES_00, BUG6152_INVALID_DATE_TZ_ABSURD,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,INVALID_DATE_TZ_ABSURD, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 5BF03C433E7 for ; Thu, 15 Oct 2020 09:59:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F17F222249 for ; Thu, 15 Oct 2020 09:59:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="MUall/o1"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="z7V9dWcn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727165AbgJOJ7q (ORCPT ); Thu, 15 Oct 2020 05:59:46 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:36628 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726157AbgJOJ7q (ORCPT ); Thu, 15 Oct 2020 05:59:46 -0400 From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1602755983; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PlevN6yVm2HnwK034FXsfndh/959DVQqNZzufhIKA04=; b=MUall/o1Ep8FjtYpBzVZioQvmMADRw3NIf1+4jtH439kFEfQO7IzV5DdgPPCuGe2H9dcGg kuu4rqtx+yhEcLgMy77E1udhVGeD1SpMD6+LIqDmauOIw/EzjDa5bySQgnqsejbxLWB3TI zewbm0x4K1tJDEVb0E7B3pReYa+RFBME9ESzd3mAC9KkGi+vLmrdRk2rcJVFoSUvmYyDoG vtDgcaxRqaQ3+XQL9exk1Nfn+io2ZeTAxqvet3P6eKF1KDU75BbTTuenrT6Qjkz4Dh3QFo McKE19QQLuWbQTNXsHTndMUA3JAixGCJVy472NJCg1EkDdciYAR0CS1bGMeMOw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1602755983; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PlevN6yVm2HnwK034FXsfndh/959DVQqNZzufhIKA04=; b=z7V9dWcnjheORrqANNNbcItCw4NhNMjaxJ1idCJ71t24jY3QPie81gGDA7E7nctNIdESAb 3zo7jyQ72+1K7TCQ== To: Sergey Senozhatsky , Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Linux-Next Mailing List , linux-mm , open list , lkft-triage@lists.linaro.org, LTP List , Andrew Morton , Mike Rapoport , Stephen Rothwell , Rasmus Villemoes , Linus Torvalds , Greg Kroah-Hartman , Thomas Gleixner , Naresh Kamboju Subject: Re: [PATCH] printk: ringbuffer: Wrong data pointer when appending small string In-Reply-To: <20201015063137.GA3668@jagdpanzerIV.localdomain> References: <20201014140514.GB17231@alley> <20201014151311.GB13775@alley> <20201014175051.GC13775@alley> <20201015063137.GA3668@jagdpanzerIV.localdomain> Date: Thu, 15 Oct 2020 12:05:42 +0206 Message-ID: <875z7bhks1.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-next@vger.kernel.org On 2020-10-15, Sergey Senozhatsky wrote: >> diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c >> index 2493348a1631..24a960a89aa8 100644 >> --- a/kernel/printk/printk_ringbuffer.c >> +++ b/kernel/printk/printk_ringbuffer.c >> @@ -1125,7 +1125,10 @@ static char *data_realloc(struct printk_ringbuffer *rb, >> >> /* If the data block does not increase, there is nothing to do. */ >> if (head_lpos - next_lpos < DATA_SIZE(data_ring)) { >> - blk = to_block(data_ring, blk_lpos->begin); >> + if (wrapped) >> + blk = to_block(data_ring, 0); >> + else >> + blk = to_block(data_ring, blk_lpos->begin); >> return &blk->data[0]; >> } > > Great catch. Indeed. I don't know how we missed that one. :-/ Reviewed-by: John Ogness