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 93CBAC7618F for ; Mon, 15 Jul 2019 14:25:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 636B9217F4 for ; Mon, 15 Jul 2019 14:25:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1563200718; bh=ZAfC2BdUPmM5ghEIJn/MUgbjJZjPlBS0RDiZJpaogD4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vHxz1FCpHOCdV8f5OzXuUyCeV/OTS8PsrAX4B+dTySLk6Y1R92ugb7XoBm42YiJF0 FUM78NGPx6nx1oprHL+hD8H4JrzCxpcFU1ddwJNTToa2zTwj3PufiTPfIZ2FIobhys 5G9COy9LVvLRwVrmelj/FphBuIwj7aTkAKg4vmLc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389194AbfGOOZQ (ORCPT ); Mon, 15 Jul 2019 10:25:16 -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: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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