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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 12268C3B1B9 for ; Fri, 14 Feb 2020 18:23:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D98202086A for ; Fri, 14 Feb 2020 18:23:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581704593; bh=dxyccyigJhbpHPCQ2eWhVt7tV6C/oCPf9Cj4BDUW/vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=sdwxhf/F6OqCQhxpcQWy08RoOlQCzaM9UCIUML1jhiNv2tmBvZl4VbWUavUn31m1d oyeeR8tRKCTDqhkx8hR6exqctj3mCufvIyASnmMBcr9gmvAiarILuTk1Z2lbeGRS6H azbyUakmJXzhYE5wxbhEP7VToFrWxiixUosZGaQo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729585AbgBNPtZ (ORCPT ); Fri, 14 Feb 2020 10:49:25 -0500 Received: from mail.kernel.org ([198.145.29.99]:52214 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729896AbgBNPtX (ORCPT ); Fri, 14 Feb 2020 10:49:23 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 96B7A2468D; Fri, 14 Feb 2020 15:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581695362; bh=dxyccyigJhbpHPCQ2eWhVt7tV6C/oCPf9Cj4BDUW/vo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rKy42ZJogbJiVIB0vxRQpET6l3+9EMQzeXR3cbqqH8r+dLG4Yki40Q9/vXKPyLlrc 7yarKQN48r11rAJTbgoegpieXLNbyRaunXVlD11md8ai+gnUkGIwD5JzMZ/z3I1qRu wUUzEpM4edvipZ9eOVQlKEwgxeAw88EDe0+iSd1A= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Remi Pommarel , Martin Blumenstingl , Jerome Brunet , Sasha Levin , linux-amlogic@lists.infradead.org, linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.5 021/542] clk: meson: pll: Fix by 0 division in __pll_params_to_rate() Date: Fri, 14 Feb 2020 10:40:13 -0500 Message-Id: <20200214154854.6746-21-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214154854.6746-1-sashal@kernel.org> References: <20200214154854.6746-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-clk-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-clk@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