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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 435CEC76186 for ; Wed, 24 Jul 2019 19:50:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 101CF22AEC for ; Wed, 24 Jul 2019 19:50:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563997843; bh=rxnY3wrfDDLzY2Euytksiym4+Ent8PQJYLcAuC5pEYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=lrswjWeafao1/1Sn/KEvfK5/zJT4IbwmTfsENN00KZnbt1ZEgvUtvznRR0469+tqo P4CiORidSRjbL0fJHdJ/eSkpTnjCf84hyicsBpRLRAeoyNpLRfoxAf5NBKCIJmYOxg braoNl0/mEufzyEp1jxvKvxKfCHv4WQ1zUUHzeMI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403867AbfGXTul (ORCPT ); Wed, 24 Jul 2019 15:50:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:59334 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391602AbfGXTud (ORCPT ); Wed, 24 Jul 2019 15:50:33 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 D5DA620665; Wed, 24 Jul 2019 19:50:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563997832; bh=rxnY3wrfDDLzY2Euytksiym4+Ent8PQJYLcAuC5pEYg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mlZH9PZ7vgFfuDXPcz0IOFy6b49nWhGfIkV1DhFRFe/tEXfLTuAKpsgfR1Vt0fZIG GnArtGzv3h1nw27l8JOpdTHlqqCuB2bxoL0vQ3tb+6I3eiDl5IJ/yTnMy9A9pop6id H3ZhW0Bkc60wElMc6d7lyo8OXsF05lhgI+Fg4OUI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ferdinand Blomqvist , Thomas Gleixner , Sasha Levin Subject: [PATCH 5.1 157/371] rslib: Fix decoding of shortened codes Date: Wed, 24 Jul 2019 21:18:29 +0200 Message-Id: <20190724191737.003107560@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190724191724.382593077@linuxfoundation.org> References: <20190724191724.382593077@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org [ Upstream commit 2034a42d1747fc1e1eeef2c6f1789c4d0762cb9c ] The decoding of shortenend codes is broken. It only works as expected if there are no erasures. When decoding with erasures, Lambda (the error and erasure locator polynomial) is initialized from the given erasure positions. The pad parameter is not accounted for by the initialisation code, and hence Lambda is initialized from incorrect erasure positions. The fix is to adjust the erasure positions by the supplied pad. Signed-off-by: Ferdinand Blomqvist Signed-off-by: Thomas Gleixner Link: https://lkml.kernel.org/r/20190620141039.9874-3-ferdinand.blomqvist@gmail.com Signed-off-by: Sasha Levin --- lib/reed_solomon/decode_rs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/lib/reed_solomon/decode_rs.c b/lib/reed_solomon/decode_rs.c index 1db74eb098d0..3313bf944ff1 100644 --- a/lib/reed_solomon/decode_rs.c +++ b/lib/reed_solomon/decode_rs.c @@ -99,9 +99,9 @@ if (no_eras > 0) { /* Init lambda to be the erasure locator polynomial */ lambda[1] = alpha_to[rs_modnn(rs, - prim * (nn - 1 - eras_pos[0]))]; + prim * (nn - 1 - (eras_pos[0] + pad)))]; for (i = 1; i < no_eras; i++) { - u = rs_modnn(rs, prim * (nn - 1 - eras_pos[i])); + u = rs_modnn(rs, prim * (nn - 1 - (eras_pos[i] + pad))); for (j = i + 1; j > 0; j--) { tmp = index_of[lambda[j - 1]]; if (tmp != nn) { -- 2.20.1