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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1635EC35296 for ; Fri, 27 May 2022 12:17:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1353776AbiE0MQT (ORCPT ); Fri, 27 May 2022 08:16:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49848 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352386AbiE0MCx (ORCPT ); Fri, 27 May 2022 08:02:53 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3F367132777; Fri, 27 May 2022 04:53:21 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id C9BC8B824D2; Fri, 27 May 2022 11:53:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BD01C385A9; Fri, 27 May 2022 11:53:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1653652391; bh=Rm0f0RVAWg6AynPmYa+oA/QouZBPXYVH9SfrC4oNYJE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=CkbHHHdGa6EN4EZzxoGENbwqzc6tYD/AZRAvsM5GfBWDYkmAKwbBtd0jCRey/PE+A Si8eMxMnsweEWNd+doaTlm5kGivhflJ3kCLK3sBNEtmEKmcORMJzRDdj4Q9DNAOU1r U/XeyjSvLpudlgHAHqfUk46z+PHj44udt0JpdkMI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , Dominik Brodowski , "Jason A. Donenfeld" Subject: [PATCH 5.15 120/145] random: do not use batches when !crng_ready() Date: Fri, 27 May 2022 10:50:21 +0200 Message-Id: <20220527084905.195699040@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220527084850.364560116@linuxfoundation.org> References: <20220527084850.364560116@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: "Jason A. Donenfeld" commit cbe89e5a375a51bbb952929b93fa973416fea74e upstream. It's too hard to keep the batches synchronized, and pointless anyway, since in !crng_ready(), we're updating the base_crng key really often, where batching only hurts. So instead, if the crng isn't ready, just call into get_random_bytes(). At this stage nothing is performance critical anyhow. Cc: Theodore Ts'o Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -467,10 +467,8 @@ static void crng_pre_init_inject(const v if (account) { crng_init_cnt += min_t(size_t, len, CRNG_INIT_CNT_THRESH - crng_init_cnt); - if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) { - ++base_crng.generation; + if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) crng_init = 1; - } } spin_unlock_irqrestore(&base_crng.lock, flags); @@ -626,6 +624,11 @@ u64 get_random_u64(void) warn_unseeded_randomness(&previous); + if (!crng_ready()) { + _get_random_bytes(&ret, sizeof(ret)); + return ret; + } + local_lock_irqsave(&batched_entropy_u64.lock, flags); batch = raw_cpu_ptr(&batched_entropy_u64); @@ -660,6 +663,11 @@ u32 get_random_u32(void) warn_unseeded_randomness(&previous); + if (!crng_ready()) { + _get_random_bytes(&ret, sizeof(ret)); + return ret; + } + local_lock_irqsave(&batched_entropy_u32.lock, flags); batch = raw_cpu_ptr(&batched_entropy_u32);