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=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 80644C433FF for ; Fri, 2 Aug 2019 10:06:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4DA6120665 for ; Fri, 2 Aug 2019 10:06:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564740375; bh=dZpLJQa/iNeL7/6UDAIQwxGQuAixpVJtkTlR0A7g43s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=No7XQddFNNH7EHQNeq5U6YMyUZSN+mheu/Dfd/QK3WKNBxwf9S81WFWsgontdOV2g todOn9+BO4YzFsHwXSZ0T94+rgoKa7xCBFP93IZie5wYN2CeJoTDgW9mcuqFxv9TRY 8+MG6wXYCL22moftsyguTNi1Y17lH1aybH+VTNiw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404687AbfHBJbd (ORCPT ); Fri, 2 Aug 2019 05:31:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:57774 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404675AbfHBJba (ORCPT ); Fri, 2 Aug 2019 05:31:30 -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 89F5D217F5; Fri, 2 Aug 2019 09:31:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564738290; bh=dZpLJQa/iNeL7/6UDAIQwxGQuAixpVJtkTlR0A7g43s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OUm8A8zxVfEau9XjtVDUNJxTdsRiUWSihD5T25tyGATZxklQyMY2yVhcBfVHB+wju LUsB13ytw40ZqZ4mhsciVlo2oCRyRM4uix7kKugbuj2VHB5956050Gi9OkdwGZYZ1Z 6gWPQdXu2ZzAUJOFnyaeVQYXUOGgima6wAdE9Q4E= 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 4.4 046/158] rslib: Fix decoding of shortened codes Date: Fri, 2 Aug 2019 11:27:47 +0200 Message-Id: <20190802092213.410364483@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190802092203.671944552@linuxfoundation.org> References: <20190802092203.671944552@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 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