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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 F3FB8C76191 for ; Mon, 15 Jul 2019 14:40:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC87D216C4 for ; Mon, 15 Jul 2019 14:40:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201636; bh=wNbhLMKQuLLNMYHuSnqZyPUBsHbPAsv1kUi64ou1XLM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vnsTcvr4F8XtFn699ViZjAaz4Ng6z4lPvdn4R41RJWjzyNq8fl04Ap2qnMRV5UoaA b5qT/PLlIHr3jWE23Rl8GQ+6HFfuJIYMa7h8fh0lEBpj30G0ors7FzlKOIRD+lq0If IoAMufDRzu61KehIjnyvgRVahhaHnKLWc73kUTAo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404470AbfGOOkf (ORCPT ); Mon, 15 Jul 2019 10:40:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:41910 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391830AbfGOOkb (ORCPT ); Mon, 15 Jul 2019 10:40:31 -0400 Received: from sasha-vm.mshome.net (unknown [73.61.17.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0E56F204FD; Mon, 15 Jul 2019 14:40:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563201630; bh=wNbhLMKQuLLNMYHuSnqZyPUBsHbPAsv1kUi64ou1XLM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lDcE7yZd6mC2pMVWpzSTb3uLhG9PPEktJb283Wc1Jur9cwraxYpFs91RETllg1fVM Ue+6SbMzlP62OCCZEnV6uHbfrpqQOhLF6A0grLl8pwrdC64mVyuyGavIlrUGxYv8Zd 967iUtwW7SJvnQ8A3N1uwjquVW0PJaunh1drKCz4= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ferdinand Blomqvist , Thomas Gleixner , Sasha Levin Subject: [PATCH AUTOSEL 4.9 58/73] rslib: Fix decoding of shortened codes Date: Mon, 15 Jul 2019 10:36:14 -0400 Message-Id: <20190715143629.10893-58-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715143629.10893-1-sashal@kernel.org> References: <20190715143629.10893-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ferdinand Blomqvist [ 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