From patchwork Sun Dec 8 21:22:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Remi Pommarel X-Patchwork-Id: 11278289 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 09EDD930 for ; Sun, 8 Dec 2019 21:14:04 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id DC08320637 for ; Sun, 8 Dec 2019 21:14:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="os7CTMTi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC08320637 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=triplefau.lt Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-Id:Date:Subject:To :From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References: List-Owner; bh=lU1LL9uPV2m2QWDyggsxnFOUWWV6mOtcgfQUpFIWbls=; b=os7CTMTipuHipB mRrsm1/Ie/DWJBGNNY01sUC+UkOBEayEXDqB2xC2WBN3jF2BueMOKDQAHdGaHIXaAGyEHYC8Vxn3A 5tkNXyEunSaFfQgN9Cp47/o7fCvYCz0bh/yJQga3NcpQvzyjRhSUiRg5woUv5hYcB3J0PRkzoX03b WJ9zEHXub3V9LqNhO3BIuCaQ/rvg/HSfUOLTJzhhkVdDJM+Y+ASUjPPEzSMs5gaXfzll1po9aJ2sJ 18h4HVfiZesVBznh/tjkqKwnCCGm9Xw2uMGF0jFXzHYGPCe4MvdW42jHmJP5hHgk3ufTxegBsxi7o QvPlUgCvr2qimSjuwk/A==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ie3sP-0003l2-B9; Sun, 08 Dec 2019 21:14:01 +0000 Received: from relay12.mail.gandi.net ([217.70.178.232]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ie3sL-0003ii-7h; Sun, 08 Dec 2019 21:13:58 +0000 Received: from localhost (unknown [88.190.179.123]) (Authenticated sender: repk@triplefau.lt) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 4C24A200006; Sun, 8 Dec 2019 21:13:41 +0000 (UTC) From: Remi Pommarel To: Neil Armstrong , Jerome Brunet Subject: [PATCH] clk: meson: pll: Fix by 0 division in __pll_params_to_rate() Date: Sun, 8 Dec 2019 22:22:06 +0100 Message-Id: <20191208212206.16808-1-repk@triplefau.lt> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191208_131357_411338_3CBC5D23 X-CRM114-Status: UNSURE ( 6.52 ) X-CRM114-Notice: Please train this message. X-Spam-Score: -0.7 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.7 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at https://www.dnswl.org/, low trust [217.70.178.232 listed in list.dnswl.org] 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.0 SPF_PASS SPF: sender matches SPF record X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Stephen Boyd , Kevin Hilman , Michael Turquette , linux-kernel@vger.kernel.org, Remi Pommarel , linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org Some meson pll registers can be initialized with 0 as N value, introducing the following division by 0 when computing rate : UBSAN: Undefined behaviour in drivers/clk/meson/clk-pll.c:75:9 division by zero CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.4.0-rc3-608075-g86c9af8630e1-dirty #400 Call trace: dump_backtrace+0x0/0x1c0 show_stack+0x14/0x20 dump_stack+0xc4/0x100 ubsan_epilogue+0x14/0x68 __ubsan_handle_divrem_overflow+0x98/0xb8 __pll_params_to_rate+0xdc/0x140 meson_clk_pll_recalc_rate+0x278/0x3a0 __clk_register+0x7c8/0xbb0 devm_clk_hw_register+0x54/0xc0 meson_eeclkc_probe+0xf4/0x1a0 platform_drv_probe+0x54/0xd8 really_probe+0x16c/0x438 driver_probe_device+0xb0/0xf0 device_driver_attach+0x94/0xa0 __driver_attach+0x70/0x108 bus_for_each_dev+0xd8/0x128 driver_attach+0x30/0x40 bus_add_driver+0x1b0/0x2d8 driver_register+0xbc/0x1d0 __platform_driver_register+0x78/0x88 axg_driver_init+0x18/0x20 do_one_initcall+0xc8/0x24c kernel_init_freeable+0x2b0/0x344 kernel_init+0x10/0x128 ret_from_fork+0x10/0x18 This checks if N is null before doing the division. Fixes: 8289aafa4f36 ("clk: meson: improve pll driver results with frac") Signed-off-by: Remi Pommarel --- drivers/clk/meson/clk-pll.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c index ddb1e5634739..6649659f216a 100644 --- a/drivers/clk/meson/clk-pll.c +++ b/drivers/clk/meson/clk-pll.c @@ -66,6 +66,10 @@ static unsigned long __pll_params_to_rate(unsigned long parent_rate, (1 << pll->frac.width)); } + /* Avoid by zero division */ + if (n == 0) + return 0; + return DIV_ROUND_UP_ULL(rate, n); }