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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, 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 CD75CC11F80 for ; Mon, 12 Jul 2021 06:49:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C501660FDB for ; Mon, 12 Jul 2021 06:49:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240509AbhGLGvz (ORCPT ); Mon, 12 Jul 2021 02:51:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:34676 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237274AbhGLGjV (ORCPT ); Mon, 12 Jul 2021 02:39:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 375C7610E5; Mon, 12 Jul 2021 06:34:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626071698; bh=GsM7kTT8tLZRHnd8pH8qOql2SjIfQ9+HXrYJLfJFeGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AnwlNfU1piA4zfhjox0LNPCxeFQYuUc6+KuSEVyKP1knBWmDg2Q5O7h2Q+fbnLkuo 0ar8i1SPtvA1ngJ+iA67TC6JHp0RwiojGpvVjttNoKXc5vDNV7EPl7OQ4Sj8brNyXI /79Sbko4crAIJhFeL4CDGrBvifKo+ttVkzt0SBj8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, kernel test robot , Richard Fitzgerald , Petr Mladek , Sasha Levin Subject: [PATCH 5.10 181/593] random32: Fix implicit truncation warning in prandom_seed_state() Date: Mon, 12 Jul 2021 08:05:41 +0200 Message-Id: <20210712060902.942060657@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060843.180606720@linuxfoundation.org> References: <20210712060843.180606720@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Richard Fitzgerald [ Upstream commit d327ea15a305024ef0085252fa3657bbb1ce25f5 ] sparse generates the following warning: include/linux/prandom.h:114:45: sparse: sparse: cast truncates bits from constant value This is because the 64-bit seed value is manipulated and then placed in a u32, causing an implicit cast and truncation. A forced cast to u32 doesn't prevent this warning, which is reasonable because a typecast doesn't prove that truncation was expected. Logical-AND the value with 0xffffffff to make explicit that truncation to 32-bit is intended. Reported-by: kernel test robot Signed-off-by: Richard Fitzgerald Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20210525122012.6336-3-rf@opensource.cirrus.com Signed-off-by: Sasha Levin --- include/linux/prandom.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/prandom.h b/include/linux/prandom.h index bbf4b4ad61df..056d31317e49 100644 --- a/include/linux/prandom.h +++ b/include/linux/prandom.h @@ -111,7 +111,7 @@ static inline u32 __seed(u32 x, u32 m) */ static inline void prandom_seed_state(struct rnd_state *state, u64 seed) { - u32 i = (seed >> 32) ^ (seed << 10) ^ seed; + u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL; state->s1 = __seed(i, 2U); state->s2 = __seed(i, 8U); -- 2.30.2