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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F2B1C35641 for ; Fri, 21 Feb 2020 08:39:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 128AB206ED for ; Fri, 21 Feb 2020 08:39:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582274341; bh=dxyccyigJhbpHPCQ2eWhVt7tV6C/oCPf9Cj4BDUW/vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=vzv+BijXYQuBZIkGMPExrdC+OiXAUQ15Nw07enzDziDGjb08Cm0dTQYiOXrAqJcbZ l/d6bX9lb9JGyYwxABWLhwEHl6znYfhXdYFUfhJLM7kilLsw3RnpQPxLzsZ+zK0OyB N3X8JU3Un5m3msJag5w2aYbx2K7/IO1w6wt82FOc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731263AbgBUIBz (ORCPT ); Fri, 21 Feb 2020 03:01:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:34120 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731246AbgBUIBr (ORCPT ); Fri, 21 Feb 2020 03:01:47 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3C4502073A; Fri, 21 Feb 2020 08:01:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582272106; bh=dxyccyigJhbpHPCQ2eWhVt7tV6C/oCPf9Cj4BDUW/vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ez8vyWWe+Zd3oCB0mCJi97G3wCIMiFESA08lgg7geBIoo8KJxMyKAGFts18QeHYYK 2YYT1mTvMZTaIDEwE4DAvgFP8asJE0lXF0Rny8dadOCqXULXqMONs7Bhq4ZxFTJhnZ 5vTMpReaQd0O4i+UgMYyRiLLnw6xZ+sIsAKS+mGw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Blumenstingl , Remi Pommarel , Jerome Brunet , Sasha Levin Subject: [PATCH 5.4 019/344] clk: meson: pll: Fix by 0 division in __pll_params_to_rate() Date: Fri, 21 Feb 2020 08:36:58 +0100 Message-Id: <20200221072350.959486973@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200221072349.335551332@linuxfoundation.org> References: <20200221072349.335551332@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Remi Pommarel [ Upstream commit d8488a41800d9f5c80bc0d17b9cc2c91b4841464 ] 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: 7a29a869434e ("clk: meson: Add support for Meson clock controller") Reviewed-by: Martin Blumenstingl Signed-off-by: Remi Pommarel [jbrunet@baylibre.com: update the comment in above the fix] Signed-off-by: Jerome Brunet Signed-off-by: Sasha Levin --- drivers/clk/meson/clk-pll.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c index ddb1e56347395..3a5853ca98c6c 100644 --- a/drivers/clk/meson/clk-pll.c +++ b/drivers/clk/meson/clk-pll.c @@ -77,6 +77,15 @@ static unsigned long meson_clk_pll_recalc_rate(struct clk_hw *hw, unsigned int m, n, frac; n = meson_parm_read(clk->map, &pll->n); + + /* + * On some HW, N is set to zero on init. This value is invalid as + * it would result in a division by zero. The rate can't be + * calculated in this case + */ + if (n == 0) + return 0; + m = meson_parm_read(clk->map, &pll->m); frac = MESON_PARM_APPLICABLE(&pll->frac) ? -- 2.20.1