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 4F93FC43458 for ; Sat, 27 Jun 2026 01:50:07 +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-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oAkJdxgsaAmyFMdkHSiVQj6HwV6946LAhWL61vW+bek=; b=Hg1lMI1/ofYgEXqtN3hXmFbvow Ll/d9NyUl+nlIDOejTEoubF+KRVosQtkX1v419PhipkIUQ7hidEVK7rY7aRA5Lx8wahRrGK7dnysj NbgIQyUNkbSeUCe7tHSnqyd39MFZZ1iPM4hrF8tLsgJKOmFX/bGaKnQgjiUD+nY3AOHQmsH8dtPOU jMreYJroX+2G0q273Wy9NB+2/tex8Ahs1mkA6wZe2Yo2bJE6eKJRG7cc+ZDOhBSMqqvbPq2RaYU94 VlDtNo2r6a0Hr1WaXePw/yLEesTB8+u8cdrEBrwwaSBUA665U7kdvJnjBHmuis1P8GjQqk6pAURpY R9p/ChoQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wdHkn-0000000C3Ci-1um8; Sat, 27 Jun 2026 01:22:41 +0000 Received: from [113.46.200.220] (helo=canpmsgout05.his.huawei.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wdHkk-0000000C3CH-3HPd for linux-arm-kernel@lists.infradead.org; Sat, 27 Jun 2026 01:22:40 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=oAkJdxgsaAmyFMdkHSiVQj6HwV6946LAhWL61vW+bek=; b=OYFkVtIdh8m8sYBjfMJzlbn82boz8hxAwipaWsE1FFTeRU8sliSaKXfe1s+teLY8L0O7PPVH8 bF6FBr5HA2WYeKB3tfD36vOZPcI2r2kuMYmVYvPYnCuXIRDlmC2F6l2GabGbWLjYH38j4ygdaCc gpkWp+lY87QvVSnpSncmij0= Received: from mail.maildlp.com (unknown [172.19.162.223]) by canpmsgout05.his.huawei.com (SkyGuard) with ESMTPS id 4gnF0n6VdTz12LDg; Sat, 27 Jun 2026 09:13:29 +0800 (CST) Received: from kwepemj100009.china.huawei.com (unknown [7.202.194.3]) by mail.maildlp.com (Postfix) with ESMTPS id 7B37C40571; Sat, 27 Jun 2026 09:22:15 +0800 (CST) Received: from DESKTOP-A37P9LK.huawei.com (10.67.109.17) by kwepemj100009.china.huawei.com (7.202.194.3) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Sat, 27 Jun 2026 09:22:14 +0800 From: Xie Yuanbin To: CC: , , , , , Subject: Re: [PATCH v3 2/2] ARM: mm: protect show_pte() in do_DataAbort() fallback path Date: Sat, 27 Jun 2026 09:22:10 +0800 Message-ID: <20260627012210.3031-1-xieyuanbin1@huawei.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.67.109.17] X-ClientProxiedBy: kwepems200002.china.huawei.com (7.221.188.68) To kwepemj100009.china.huawei.com (7.202.194.3) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260626_182239_318646_75EB5271 X-CRM114-Status: GOOD ( 13.89 ) 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 On Fri, 26 Jun 2026 13:37:00 +0100, Russell King wrote: > On Fri, Jun 26, 2026 at 06:16:15PM +0800, Xie Yuanbin wrote: >> I suggest that waiting for this patch to be merged first: >> https://lore.kernel.org/20260625122612.43501-1-xieyuanbin1@huawei.com >> which make sure that interrupts are enabled here. > > No, it doesn't ensure that. Oh, I'm sorry my description wasn't clear. It should make sure that for user unhandled faults, interrupts are enabled here, without kernel unhandled faults. > We are not "fixing" show_pte(), which is a diagnostic function when > things go wrong in the kernel, and is there to *try* to give us > information to diagnose what happened. It is *not* a function that > is used routinely in the kernel. For kernel faults, I fully agree with it. However, for user faults, I think "fixing" is necessary. We might be able to construct a user-mode program in some way to repeatedly trigger unhandled faults -> show_pte(), such as executing bkpt instruction, or something else, and then the kernel panic, this may be a security vulnerability.