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=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 22B4FC07E99 for ; Mon, 5 Jul 2021 15:35:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F96D610A6 for ; Mon, 5 Jul 2021 15:35:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233733AbhGEPiY (ORCPT ); Mon, 5 Jul 2021 11:38:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:58662 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233007AbhGEPgV (ORCPT ); Mon, 5 Jul 2021 11:36:21 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B00DE61A36; Mon, 5 Jul 2021 15:32:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1625499121; bh=nFiVBD9s1F0BKiFDeyhGID7OC5rzFoiX0HeTvFie4L0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=VEegOiPbt/awpcGMJr84F04NkegOwZN0/lNCbB6Sc60Idtrb7c0/7+ZP5PYD0ZrOe s9Me5PF/GKWaMQJaJrs/X4Z9qvzLSWasGYA0BdzkVfQuKqY2AIw/V9zFNTjq4jEIVE ds/dNt22Y9iHS4NkcJ+bbUeMIjMPdo6DTL9swjNfww2XcElZ29jGXyCTTAJdgVa5qS oShl1fklfh80ALmsiPk1YsRASKE+Vimf3hoNQ2hZwm3t1fkH0kyx5oiQnbwEWwdgRe SjL59sWvDid0qrGoX6e+i5UYZ02WSQFAZPt9y+vChJTZjHr/htRfEQ+WgO1MkP5HUB gXFVI4GDAOiUQ== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Richard Fitzgerald , kernel test robot , Petr Mladek , Sasha Levin Subject: [PATCH AUTOSEL 4.9 4/9] random32: Fix implicit truncation warning in prandom_seed_state() Date: Mon, 5 Jul 2021 11:31:50 -0400 Message-Id: <20210705153155.1522423-4-sashal@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210705153155.1522423-1-sashal@kernel.org> References: <20210705153155.1522423-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 cc1e71334e53..e20339c78a84 100644 --- a/include/linux/prandom.h +++ b/include/linux/prandom.h @@ -93,7 +93,7 @@ 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