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 D7761C43334 for ; Thu, 23 Jun 2022 16:55:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231852AbiFWQzB (ORCPT ); Thu, 23 Jun 2022 12:55:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49184 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233896AbiFWQvu (ORCPT ); Thu, 23 Jun 2022 12:51:50 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4E86A18347; Thu, 23 Jun 2022 09:51:05 -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 D82D961F99; Thu, 23 Jun 2022 16:51:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A1584C3411B; Thu, 23 Jun 2022 16:51:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1656003064; bh=ubl00wQY+xv98jqQqIiGIqc9PiUm+TumNEpqlkQaCZ8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sXKDuCqRZ9FRuy0zQ0lOnWt4coKOUV8rLlN22rdQhVXW5CF+VNLZBUxFjX9fya57A ElOGj0HvMswINy1efD33F1JxGcuZyYW8aIq+0H6iKz4fp+H0D87Gim0mN8GuTQTAts 38VK5JLU6J9eUb/MOEaz2AfCIcwlBPvgAzcyOfWI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dominik Brodowski , Eric Biggers , "Jason A. Donenfeld" Subject: [PATCH 4.9 117/264] random: fix locking in crng_fast_load() Date: Thu, 23 Jun 2022 18:41:50 +0200 Message-Id: <20220623164347.378827219@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220623164344.053938039@linuxfoundation.org> References: <20220623164344.053938039@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 7c2fe2b32bf76441ff5b7a425b384e5f75aa530a upstream. crng_init is protected by primary_crng->lock, so keep holding that lock when incrementing crng_init from 0 to 1 in crng_fast_load(). The call to pr_notice() can wait until the lock is released; this code path cannot be reached twice, as crng_fast_load() aborts early if crng_init > 0. Signed-off-by: Dominik Brodowski Reviewed-by: Eric Biggers Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman --- drivers/char/random.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -647,12 +647,13 @@ static size_t crng_fast_load(const u8 *c p[crng_init_cnt % CHACHA20_KEY_SIZE] ^= *cp; cp++; crng_init_cnt++; len--; ret++; } - spin_unlock_irqrestore(&primary_crng.lock, flags); if (crng_init_cnt >= CRNG_INIT_CNT_THRESH) { invalidate_batched_entropy(); crng_init = 1; - pr_notice("fast init done\n"); } + spin_unlock_irqrestore(&primary_crng.lock, flags); + if (crng_init == 1) + pr_notice("fast init done\n"); return ret; }