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 94724C433FF for ; Mon, 29 Jul 2019 20:14:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5AB09205F4 for ; Mon, 29 Jul 2019 20:14:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564431283; bh=dZpLJQa/iNeL7/6UDAIQwxGQuAixpVJtkTlR0A7g43s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=CxymAk88BfrR6LTxddRUFUzWoRauOpWkZeztfoxb/wSwA91EpmR8d6BQEFnXLdF77 KV61vu+M3M8zcc2Ij0htrxksWZC5KRKqZRQYsVLg95ifelaGADwV1pdJDGHVwjcwzD Hfz/bT0b+i/WbA4RN8Daeeqv0BHovkCixw95ESy4= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726958AbfG2T1i (ORCPT ); Mon, 29 Jul 2019 15:27:38 -0400 Received: from mail.kernel.org ([198.145.29.99]:40227 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729929AbfG2T1h (ORCPT ); Mon, 29 Jul 2019 15:27:37 -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 C38DA217D4; Mon, 29 Jul 2019 19:27:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564428456; bh=dZpLJQa/iNeL7/6UDAIQwxGQuAixpVJtkTlR0A7g43s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n5v4VLbUzNRfJ9xXM/DBIYAGxEc91hO0s7oKZLpAPxk2DbzKmtTDnKCDuEd85pbGY yOr4Q9fB+FNO6K9Uh1tg0JEZQc1sEzPaOL6ZOWohPhylH10Ewp5oi9bAg6ai+3BGYu 0aKKjOZ9rbAL8sRrOaA30o3LoQ5zMjkriB6Wf3NI= 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 4.14 082/293] rslib: Fix decoding of shortened codes Date: Mon, 29 Jul 2019 21:19:33 +0200 Message-Id: <20190729190830.909403836@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190729190820.321094988@linuxfoundation.org> References: <20190729190820.321094988@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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 0ec3f257ffdf..8eed0f9ac495 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