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 B6934C433EF for ; Thu, 23 Jun 2022 18:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231796AbiFWSAV (ORCPT ); Thu, 23 Jun 2022 14:00:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51244 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235883AbiFWR5r (ORCPT ); Thu, 23 Jun 2022 13:57:47 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AFA8C6F4B3; Thu, 23 Jun 2022 10:15:51 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 1C73861E0F; Thu, 23 Jun 2022 17:15:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E21ACC3411B; Thu, 23 Jun 2022 17:15:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656004550; bh=loYafYE5zjmnYdIqVer8tgs+VwSnZs+hHbLy9ZNlDUg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JOUsGWTZZF+JKHkRdCCMJR1/j1c2oixopmI3IIWgjEeRPYG3tIfY+/caRs4NjpiA9 SZz1stXlV9gEcqhp39XCoJzne+aXTpp4nortjdybazpkyYVYi9zNDorwI50XG+AA81 A3k8S/IKK6DZhp02ntneKKdX+NAMuW7WcQp2nLa8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Herbert Xu , "Jason A. Donenfeld" , Dominik Brodowski Subject: [PATCH 4.19 072/234] random: continually use hwgenerator randomness Date: Thu, 23 Jun 2022 18:42:19 +0200 Message-Id: <20220623164345.097775946@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164343.042598055@linuxfoundation.org> References: <20220623164343.042598055@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: Dominik Brodowski commit c321e907aa4803d562d6e70ebed9444ad082f953 upstream. The rngd kernel thread may sleep indefinitely if the entropy count is kept above random_write_wakeup_bits by other entropy sources. To make best use of multiple sources of randomness, mix entropy from hardware RNGs into the pool at least once within CRNG_RESEED_INTERVAL. Cc: Herbert Xu Cc: Jason A. Donenfeld Signed-off-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2193,13 +2193,15 @@ void add_hwgenerator_randomness(const ch return; } - /* Suspend writing if we're above the trickle threshold. + /* Throttle writing if we're above the trickle threshold. * We'll be woken up again once below random_write_wakeup_thresh, - * or when the calling thread is about to terminate. + * when the calling thread is about to terminate, or once + * CRNG_RESEED_INTERVAL has lapsed. */ - wait_event_interruptible(random_write_wait, + wait_event_interruptible_timeout(random_write_wait, !system_wq || kthread_should_stop() || - POOL_ENTROPY_BITS() <= random_write_wakeup_bits); + POOL_ENTROPY_BITS() <= random_write_wakeup_bits, + CRNG_RESEED_INTERVAL); mix_pool_bytes(buffer, count); credit_entropy_bits(entropy); }