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 F2B25FA3742 for ; Thu, 27 Oct 2022 17:01:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236289AbiJ0RBU (ORCPT ); Thu, 27 Oct 2022 13:01:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54188 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236819AbiJ0RBT (ORCPT ); Thu, 27 Oct 2022 13:01:19 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6D0D7188585 for ; Thu, 27 Oct 2022 10:01:18 -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 0990E623F0 for ; Thu, 27 Oct 2022 17:01:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16E73C433C1; Thu, 27 Oct 2022 17:01:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666890077; bh=QuuSza65jqo4t82p5OwJsQaS4BBVh8/TeEiRr7ZKkqs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=1fpJqwG/oQWcWOgmSop2cGuylkcxOR1a8M+1FLPhUT3o1T0r0r/uDy9dXSHj3XkvJ sbcpd3yPAB9tXr147hrFKiqvPrU217wJ03Z1PvixvFSxOlRnMyIVzeRtmEGRFVKEPT KDff282rl5AdAJNtenL/EPCxYTagVDicdoXexbfE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fabien Parent , Viresh Kumar Subject: [PATCH 5.15 14/79] cpufreq: qcom: fix writes in read-only memory region Date: Thu, 27 Oct 2022 18:55:12 +0200 Message-Id: <20221027165055.435153948@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221027165054.917467648@linuxfoundation.org> References: <20221027165054.917467648@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Fabien Parent commit 01039fb8e90c9cb684430414bff70cea9eb168c5 upstream. This commit fixes a kernel oops because of a write in some read-only memory: [ 9.068287] Unable to handle kernel write to read-only memory at virtual address ffff800009240ad8 ..snip.. [ 9.138790] Internal error: Oops: 9600004f [#1] PREEMPT SMP ..snip.. [ 9.269161] Call trace: [ 9.276271] __memcpy+0x5c/0x230 [ 9.278531] snprintf+0x58/0x80 [ 9.282002] qcom_cpufreq_msm8939_name_version+0xb4/0x190 [ 9.284869] qcom_cpufreq_probe+0xc8/0x39c ..snip.. The following line defines a pointer that point to a char buffer stored in read-only memory: char *pvs_name = "speedXX-pvsXX-vXX"; This pointer is meant to hold a template "speedXX-pvsXX-vXX" where the XX values get overridden by the qcom_cpufreq_krait_name_version function. Since the template is actually stored in read-only memory, when the function executes the following call we get an oops: snprintf(*pvs_name, sizeof("speedXX-pvsXX-vXX"), "speed%d-pvs%d-v%d", speed, pvs, pvs_ver); To fix this issue, we instead store the template name onto the stack by using the following syntax: char pvs_name_buffer[] = "speedXX-pvsXX-vXX"; Because the `pvs_name` needs to be able to be assigned to NULL, the template buffer is stored in the pvs_name_buffer and not under the pvs_name variable. Cc: v5.7+ # v5.7+ Fixes: a8811ec764f9 ("cpufreq: qcom: Add support for krait based socs") Signed-off-by: Fabien Parent Signed-off-by: Viresh Kumar Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/qcom-cpufreq-nvmem.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/cpufreq/qcom-cpufreq-nvmem.c +++ b/drivers/cpufreq/qcom-cpufreq-nvmem.c @@ -264,7 +264,8 @@ static int qcom_cpufreq_probe(struct pla struct nvmem_cell *speedbin_nvmem; struct device_node *np; struct device *cpu_dev; - char *pvs_name = "speedXX-pvsXX-vXX"; + char pvs_name_buffer[] = "speedXX-pvsXX-vXX"; + char *pvs_name = pvs_name_buffer; unsigned cpu; const struct of_device_id *match; int ret;