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 487B3CFD2F6 for ; Thu, 27 Nov 2025 11:21:36 +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=DodGNQ4J3R60otr7WXzwptpN2trZwaXPd+16aznDXKU=; b=QryYZfc2nela7/olRILYBOuj1v fC/6muEJ/NGHnexd4qB+YamZwwEv1SkJT4eqwbFN5VOFCbED0IqQZqVTBpSTUeA0EsoydntzZXBjw Fv5EZrrXehd0HyxiPnttrW9AizqD/UUUmXLhK1ba2NMTdp4+VKte0mI0N78DNPM4xFC6bmdOWuRd9 JHCcpRM5cA/w+68ULS+v8vtIA1oWf70zyVVPQfroEsDxNP7dxSSooE85HgHL7eLPPx56m3naTxXok FxwnNpSB1zbl9qAzBwVu/bdMyoitkVhQwza5Dp00ygPx6dQVm0tOD2oi6aBGpVQphoeCbOncc/1L2 XSjdZzpw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vOa42-0000000GRkZ-1CHb; Thu, 27 Nov 2025 11:21:30 +0000 Received: from canpmsgout10.his.huawei.com ([113.46.200.225]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vOa3z-0000000GRjo-2YMS for linux-arm-kernel@lists.infradead.org; Thu, 27 Nov 2025 11:21:29 +0000 dkim-signature: v=1; a=rsa-sha256; d=huawei.com; s=dkim; c=relaxed/relaxed; q=dns/txt; h=From; bh=DodGNQ4J3R60otr7WXzwptpN2trZwaXPd+16aznDXKU=; b=kzAHUMF2dUX/75F2x8k4f67X3bwt94v+LeKbd6y1I+Pfnt/W9chF7FpLBH1NgTjP/L/NGfo8n xvIQ0+PuPafeVGbUpzBFi9IJnhCxY1y3YnVnFQlCNNtgM7nYb04k1porCfASxHwGKtjxPIckwVs 1urT6Cq6FxhqN1lH2J74Qto= Received: from mail.maildlp.com (unknown [172.19.162.112]) by canpmsgout10.his.huawei.com (SkyGuard) with ESMTPS id 4dHDTl6J2qz1K96R; Thu, 27 Nov 2025 19:19:23 +0800 (CST) Received: from kwepemj100009.china.huawei.com (unknown [7.202.194.3]) by mail.maildlp.com (Postfix) with ESMTPS id CD7A614011F; Thu, 27 Nov 2025 19:21:10 +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 15.2.1544.11; Thu, 27 Nov 2025 19:21:09 +0800 From: Xie Yuanbin To: , , , , , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , Xie Yuanbin Subject: Re: [RFC PATCH] vfs: Fix might sleep in load_unaligned_zeropad() with rcu read lock held Date: Thu, 27 Nov 2025 19:20:35 +0800 Message-ID: <20251127112035.129014-1-xieyuanbin1@huawei.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251127072057.EbvhUyG4@linutronix.de> References: <20251127072057.EbvhUyG4@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.67.109.17] X-ClientProxiedBy: kwepems500001.china.huawei.com (7.221.188.70) To kwepemj100009.china.huawei.com (7.202.194.3) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251127_032127_827328_0620CB18 X-CRM114-Status: GOOD ( 11.13 ) 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, Thu, 27 Nov 2025 08:20:57 +0100, Sebastian Andrzej Siewior wrote: > This all should be covered by the series here > https://lore.kernel.org/all/20251110145555.2555055-1-bigeasy@linutronix.de/ Yes, I know it. > or do I miss something. We had some discussions about this bug: Link: https://lore.kernel.org/lkml/20251126090505.3057219-1-wozizhi@huaweicloud.com/ The discussions: Link: https://lore.kernel.org/CAHk-=wh1Wfwt9OFB4AfBbjyeu4JVZuSWQ4A8OoT3W6x9btddfw@mail.gmail.com Link: https://lore.kernel.org/20251126192640.GD3538@ZenIV Link: https://lore.kernel.org/aSeNtFxD1WRjFaiR@shell.armlinux.org.uk According to the discussion, in do_page_fault(), when addr >= TASK_SIZE, we should not try to acquire the mm read lock or find vma. Instead, we should directly call __do_kernel_fault() or __do_user_fault(). Your submission just moved harden_branch_predictor() forward. I think we can have more discussions about the patches to fix the missing spectre. I am trying to write a new patch, I hope it will better handle these two bugs and be compatible with PREEMPT_RT scenarios. > Sebastian Thanks! Xie Yuanbin