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 236BEC56205 for ; Thu, 6 Aug 2026 15:39:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2sen4rUQ02mp1eQb0BatJNlEZOouuwz1/74UC5nlKG4=; b=VRIg8XI3AsJ3L2qNtOmBoeduL/ ZEkaKmSqbZne3S+A7CxbhVIxa9X3X1dxTYZkIenXEn2DxQKuTVAuRkRmrBbH/CEYLkW2DuiatZ93t St6cmlFQd03P3Gk22r+GYflCZnZMyXwkI53FxnXaWXexQ3YsgddEZGZUQin2xGrL5yl4Tw755Vz/m gf38UFm5/NqgzujpQnhDwkIeyx7JYleD7r/BDj2QuPeryK+3GRE5jSuatUu39SIKRCRcns8GmhWQq I/QUtmenEzuY7hfX3KrgMYR8PKrDhLFsd+2kmURmL1vm+4BlQ1zZwsjtNskdOXpYD+wCRVHOfQt+u 0Tr7F8vQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1ws0BG-000000067LE-01d3; Thu, 06 Aug 2026 15:38:50 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1ws0BD-000000067KP-0PGc for linux-arm-kernel@lists.infradead.org; Thu, 06 Aug 2026 15:38:48 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id ABC36153B; Thu, 6 Aug 2026 08:38:37 -0700 (PDT) Received: from [192.168.178.24] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0CEEB3F632; Thu, 6 Aug 2026 08:38:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1786030721; bh=HkLd7vLJFCtccjkU6wFw/hXH3/rpNOn5YATvCZNVC+A=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=CFPIzaNY91u1RSDpvqJJ7p/ocphehLxg9n9kmE7Ly9JxhpAaQr2tu0N5Lk7gLMghr cHiD9Fyeh5iX8Pm4iDItyJoEwVg4WrcKysZMdylN5SJWI9evy4nGvusdMnGqNSy377 mBcX9+hP8wlyHCd2ex+1lUttkfMhcp+VQdc77TkY= Message-ID: <51f5d369-9491-49cb-957a-dd70ad42ecd6@arm.com> Date: Thu, 6 Aug 2026 17:38:27 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 1/2] arm_mpam: Fix a NULL pointer dereference on unbinding after an error interrupt To: Ben Horgan Cc: james.morse@arm.com, reinette.chatre@intel.com, fenghuay@nvidia.com, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, dave.martin@arm.com, will@kernel.org, catalin.marinas@kernel.org References: <20260806144631.2502918-1-ben.horgan@arm.com> <20260806144631.2502918-2-ben.horgan@arm.com> Content-Language: en-GB From: Andre Przywara In-Reply-To: <20260806144631.2502918-2-ben.horgan@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260806_083847_191162_482AB7CC X-CRM114-Status: GOOD ( 17.89 ) 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi, On 8/6/26 16:46, Ben Horgan wrote: > If a user unbinds an MSC after mpam_disable() has been run in response > to an error interrupt then a dereference of a NULL pointer occurs as > mpam_disable() sets the drvdata to NULL. Add an early return to the driver > remove callback to avoid this. Yes, I added a very similar patch to my stack yesterday, in response to a Sashiko complaint. However I was still calling mpam_free_garbage() at the end, to me it looks like this is not depending on any MSC? Cheers, Andre > Fixes: f04046f2577a ("arm_mpam: Add probe/remove for mpam msc driver and kbuild boiler plate") > Signed-off-by: Ben Horgan > --- > drivers/resctrl/mpam_devices.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c > index 2f09f4b78bd3..bc6cc0b5c96b 100644 > --- a/drivers/resctrl/mpam_devices.c > +++ b/drivers/resctrl/mpam_devices.c > @@ -2025,6 +2025,9 @@ static void mpam_msc_drv_remove(struct platform_device *pdev) > { > struct mpam_msc *msc = platform_get_drvdata(pdev); > > + if (!msc) > + return; > + > mutex_lock(&mpam_list_lock); > mpam_msc_destroy(msc); > mutex_unlock(&mpam_list_lock);