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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 74346C433FE for ; Fri, 14 Oct 2022 11:08:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=eUpMW1a1s+3QR3vDj1ftrAcbBelqVZdNJxYdvIF1J3A=; b=KtGOeXgMSu/Jea X1vbkC1hVH5Tk2w1NgpU9QzrKOla62lVgGk6C72m9TVqVYzkVQ2izlL0Le+WTpRj5rvWkFSaGEBNw 9N8famvndEQTBNnXlOW5qvjXd3p1Ku/lpR+YqiZ7lidVbg8mRdUFTh0Cqtq3RYTrPFZ4CYV01ryKI sE6p0rtoDZlDPgRbJLBl7Iz31YfiihsRBNlibx0MOIl1GL2NhuP78cSoNP9emVUNf9pAykQY9ylK7 1A/vGs6nwl5UgaRtGXdEu5AZn9Ibvz5N69u1N1RdWr/gDiFrkcrN/PhGsVrBSg2p7fHbGJC/Ok26U MgynDexxKDZpO6q/xZ8w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ojIWn-00EUbC-G7; Fri, 14 Oct 2022 11:06:57 +0000 Received: from helcar.hmeau.com ([216.24.177.18] helo=fornost.hmeau.com) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1ojIWg-00EUWz-SG; Fri, 14 Oct 2022 11:06:54 +0000 Received: from gwarestrin.arnor.me.apana.org.au ([192.168.103.7]) by fornost.hmeau.com with smtp (Exim 4.94.2 #2 (Debian)) id 1ojIWF-00EgYJ-Ny; Fri, 14 Oct 2022 22:06:24 +1100 Received: by gwarestrin.arnor.me.apana.org.au (sSMTP sendmail emulation); Fri, 14 Oct 2022 19:06:23 +0800 Date: Fri, 14 Oct 2022 19:06:23 +0800 From: Herbert Xu To: "Jason A. Donenfeld" Cc: Mark Brown , Florian Fainelli , Dominik Brodowski , kernelci-results@groups.io, bot@kernelci.org, gtucker@collabora.com, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] hw_random: bcm2835: use hwrng_msleep() instead of cpu_relax() Message-ID: References: <20221010150607.720600-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20221010150607.720600-1-Jason@zx2c4.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221014_040650_926773_D40B3F16 X-CRM114-Status: GOOD ( 13.46 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Oct 10, 2022 at 09:06:07AM -0600, Jason A. Donenfeld wrote: > Rather than busy looping, yield back to the scheduler and sleep for a > bit in the event that there's no data. This should hopefully prevent the > stalls that Mark reported: > > <6>[ 3.362859] Freeing initrd memory: 16196K > <3>[ 23.160131] rcu: INFO: rcu_sched self-detected stall on CPU > <3>[ 23.166057] rcu: 0-....: (2099 ticks this GP) idle=03b4/1/0x40000002 softirq=28/28 fqs=1050 > <4>[ 23.174895] (t=2101 jiffies g=-1147 q=2353 ncpus=4) > <4>[ 23.180203] CPU: 0 PID: 49 Comm: hwrng Not tainted 6.0.0 #1 > <4>[ 23.186125] Hardware name: BCM2835 > <4>[ 23.189837] PC is at bcm2835_rng_read+0x30/0x6c > <4>[ 23.194709] LR is at hwrng_fillfn+0x71/0xf4 > <4>[ 23.199218] pc : [] lr : [] psr: 40000033 > <4>[ 23.205840] sp : f093df70 ip : 00000000 fp : 00000000 > <4>[ 23.211404] r10: c3c7e800 r9 : 00000000 r8 : c17e6b20 > <4>[ 23.216968] r7 : c17e6b64 r6 : c18b0a74 r5 : c07ccd99 r4 : c3f171c0 > <4>[ 23.223855] r3 : 000fffff r2 : 00000040 r1 : c3c7e800 r0 : c3f171c0 > <4>[ 23.230743] Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA Thumb Segment none > <4>[ 23.238426] Control: 50c5387d Table: 0020406a DAC: 00000051 > <4>[ 23.244519] CPU: 0 PID: 49 Comm: hwrng Not tainted 6.0.0 #1 > > Link: https://lore.kernel.org/all/Y0QJLauamRnCDUef@sirena.org.uk/ > Signed-off-by: Jason A. Donenfeld > --- > I haven't tested this. Somebody with access to that kernel CI infra that > triggered this will need to test. > > drivers/char/hw_random/bcm2835-rng.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Patch applied. Thanks. -- Email: Herbert Xu Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel