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 B388FD11193 for ; Wed, 26 Nov 2025 18:55:51 +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:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=MLgia25EvIAIBo0VY2I6S9Dk4/MSQiPdMJldJvpcdsU=; b=bRDmsTnY/AO5egSvDDIAcosCW1 Rhlp7BZBNi1e2YEj5iDZme8xvfj5C3k5lh1lFJZaMYBeBxHH7BIbbfMZT3EMJd+1Nj1VDhz+57uv9 jTGxrYkaq/gE3RlC5Nav7fEjzFGEIG2YcD/3MqulA1O2BHBKWoagZC08EZxW9k9i5UKCb/toVOtoX zQLNLEHaK7zelGwqcRNES3w5fOlWbyfz1X2Jxi9m+apILt9m+kOFH+eMP6BL9YQ6+7lKU3AMrj9dT yGrFdSE/5cQn8x8IgTWnB7bcI3hWGnCgA5ptUi1Hl9c2Z4RRtMPP8DMI4pcL7BxVpaLysH02eEWjH ocdc5tow==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vOKg9-0000000FWMW-0MZ5; Wed, 26 Nov 2025 18:55:49 +0000 Received: from zeniv.linux.org.uk ([2a03:a000:7:0:5054:ff:fe1c:15ff]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vOKg6-0000000FWM9-388A for linux-arm-kernel@lists.infradead.org; Wed, 26 Nov 2025 18:55:47 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=linux.org.uk; s=zeniv-20220401; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=MLgia25EvIAIBo0VY2I6S9Dk4/MSQiPdMJldJvpcdsU=; b=g3nS6R4bW6uQlx6Je24W9afEMH Em5LKt9oz497k9Gfvq/XJ6/fvEKedQW3YCWBUH4PKFDdicr4JXoufcWgeWK7ZSKU746ud4sumvmfV YFNnq6xLzJPiACvsBcuyfVcSUnV3OpxMuva5TL3RuNuU+TffZJW9CUynU/dVu/G8lWvJ3b7YIKkhz 9yZ6mCKUXqeuIpWgtJErxKkaN0GEn3IPqwa/y96rIxsDaXZooIrwB2XiggY7muOwYj/KzbZGUgbxZ SF/CXLaEIOq6KfcuVZfyq7VCgkA0OMCSds/ICAlTsKJdpjSM1Wvsnw4PrjBCCA8I8x400e1Wrl1WS zsOaQ43Q==; Received: from viro by zeniv.linux.org.uk with local (Exim 4.99 #2 (Red Hat Linux)) id 1vOKg5-000000007j8-2ErT; Wed, 26 Nov 2025 18:55:45 +0000 Date: Wed, 26 Nov 2025 18:55:45 +0000 From: Al Viro To: Zizhi Wo Cc: jack@suse.com, brauner@kernel.org, hch@lst.de, akpm@linux-foundation.org, linux@armlinux.org.uk, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, wozizhi@huawei.com, yangerkun@huawei.com, wangkefeng.wang@huawei.com, pangliyuan1@huawei.com, xieyuanbin1@huawei.com Subject: Re: [Bug report] hash_name() may cross page boundary and trigger sleep in RCU context Message-ID: <20251126185545.GC3538@ZenIV> References: <20251126090505.3057219-1-wozizhi@huaweicloud.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251126090505.3057219-1-wozizhi@huaweicloud.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251126_105546_784781_29B94F32 X-CRM114-Status: UNSURE ( 8.72 ) X-CRM114-Notice: Please train this message. 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 Wed, Nov 26, 2025 at 05:05:05PM +0800, Zizhi Wo wrote: > under an RCU read-side critical section. In linux-mainline, arm/arm64 > do_page_fault() still has this problem: > > lock_mm_and_find_vma->get_mmap_lock_carefully->mmap_read_lock_killable. arm64 shouldn't hit do_page_fault() in the first place, and do_translation_fault() there will see that address is beyond TASK_SIZE and go straight to do_bad_area() -> __do_kernel_fault() -> fixup_exception(), with no messing with mmap_lock. Can anybody confirm that problem exists on arm64 (ideally - with reproducer)?