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=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 F03D2C76191 for ; Mon, 15 Jul 2019 14:25:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B36BA21537 for ; Mon, 15 Jul 2019 14:25:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200720; bh=ZAfC2BdUPmM5ghEIJn/MUgbjJZjPlBS0RDiZJpaogD4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=UO8mGpLz2cWFmGazO25VYWSiuqXsFSFacw/ZpAe6OE9vLDJUzDPJDl6U6xBLXOg8b Cup8p8VBymEjtCDnPXhbSptmFRbpxtB8/pqTCrokZwfWimuuxYtj8zRywlCnbp7f2K AYoM+bccGvEo1j20XzaIQkT6B7DJan+X9NBG0iZM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390538AbfGOOZT (ORCPT ); Mon, 15 Jul 2019 10:25:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:60040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391214AbfGOOZM (ORCPT ); Mon, 15 Jul 2019 10:25:12 -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 09A342053B; Mon, 15 Jul 2019 14:25:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200711; bh=ZAfC2BdUPmM5ghEIJn/MUgbjJZjPlBS0RDiZJpaogD4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=K/J+dFh+A6XshTUkoWkvQqTOSQpAScGUoh+N851dirkERZF2kGAWQ/y/UPwQhp7+S BWF02nE33KZtE8dvTyZvqbBtNJciov1iPUTnahKDWJA5Ep60KEXyOomZCwsh9ej8Wi lMRnI4/f9FqdYu3HC+JAjQ/Bqqt1Btn2eXcxT6mE= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ferdinand Blomqvist , Thomas Gleixner , Sasha Levin Subject: [PATCH AUTOSEL 4.19 115/158] rslib: Fix decoding of shortened codes Date: Mon, 15 Jul 2019 10:17:26 -0400 Message-Id: <20190715141809.8445-115-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190715141809.8445-1-sashal@kernel.org> References: <20190715141809.8445-1-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 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