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 60056CFD376 for ; Sun, 30 Nov 2025 11:20:26 +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=gPPSeu511L0k6gL1IYpux6jfrEM3Z2mSgCdofcykt0M=; b=cecriPR1xacoSEOk3t9xb9NBef GcIpWLhjP4itRmNALnWFJ66I9RXdiE+wevi9vpedqG8fgnMk+ysY97SVwMw890Q7a7jot8m6J0epU xy/NjH0RFq9HyoGG7vO2PFE+DwUP2TwSue0kHHVI5oabZ0QMmErkhqVYv/LWzPgd3+LaFmE7Oe/Zt eMWQLUGWw/LEPajV90tzk6CdWmwSwTt7yarYzzvTeruPehZk7uWiBYJA1ymAnI8MIQqL7+DAfWzit 7ZB+spiqeIMbn/xUMagBJ+sBlyT0atOIGfexYnSgkvfkBPIqRE7e4JIY3y796Ub9JmpmGSMmTnWFU 1/1hpknw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vPfTW-00000002Fnl-37Ap; Sun, 30 Nov 2025 11:20:18 +0000 Received: from galois.linutronix.de ([2a0a:51c0:0:12e:550::1]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vPfTU-00000002FnC-0ENu for linux-arm-kernel@lists.infradead.org; Sun, 30 Nov 2025 11:20:17 +0000 Date: Sun, 30 Nov 2025 12:20:08 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1764501610; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gPPSeu511L0k6gL1IYpux6jfrEM3Z2mSgCdofcykt0M=; b=H/O9ZzYiHw/2G2WBqoGZ3K3FPLNuLrAWvk4v/z+wfncXBs075k6aX+F8Iqp8Vgp+LcjyHC z1G/MHOyvAh7TA4mK+eXChXlqCIy+EZvNiofVHBTXaCED1jIhLqVlWUxXvtoHpu1Ah9S2e F9JX+agQqQ/wqp8/A44N9X3E6LhxoLVaz+GSa+Dj2DBQ++P2UMEGoJSFjvRTB6wNi21E8W 3esGxnfRtGW9Xy9r7VrNCc6RRigIODj87/eRuf/oAicuV8uZFco5gHUlYiB3CiXIVKxoYP MZ7+6xcVMAYjC7Z8e8XAfZYx6UOUYsx3qf+zjw3RwTW8FcJLWYP9IkNoABFSNQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1764501610; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=gPPSeu511L0k6gL1IYpux6jfrEM3Z2mSgCdofcykt0M=; b=8RrraBCZU5plsGR6xmde28IoY0RzxSIbtXdVMZm7XVpNQnachUBhpN47q/W3YXgJIb0ERh gNxYivhVx7Dx+TBw== From: Sebastian Andrzej Siewior To: "Russell King (Oracle)" Cc: Xie Yuanbin , akpm@linux-foundation.org, arnd@arndb.de, brauner@kernel.org, david.laight@runbox.com, hch@lst.de, jack@suse.com, kuninori.morimoto.gx@renesas.com, liaohua4@huawei.com, lilinjie8@huawei.com, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, lorenzo.stoakes@oracle.com, marc.zyngier@arm.com, nico@fluxnic.net, pangliyuan1@huawei.com, pfalcato@suse.de, punitagrawal@gmail.com, rjw@rjwysocki.net, rppt@kernel.org, tony@atomide.com, vbabka@suse.cz, viro@zeniv.linux.org.uk, wangkefeng.wang@huawei.com, will@kernel.org, wozizhi@huaweicloud.com Subject: Re: [RFC PATCH v2 1/2] ARM/mm/fault: always goto bad_area when handling with page faults of kernel address Message-ID: <20251130112008.DZYHlSPm@linutronix.de> References: <20251127145127.qUXs_UAE@linutronix.de> <20251128022756.9973-1-xieyuanbin1@huawei.com> <20251128120359.Xc09qn1W@linutronix.de> <20251128172242.cCNBVf7H@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251130_032016_241776_A0575F07 X-CRM114-Status: GOOD ( 25.81 ) 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 2025-11-28 17:34:31 [+0000], Russell King (Oracle) wrote: > On Fri, Nov 28, 2025 at 06:22:42PM +0100, Sebastian Andrzej Siewior wrote: > > On 2025-11-28 17:01:18 [+0000], Russell King (Oracle) wrote: > > > > I hope Russell will add them once he gets to it. They got reviewed, I > > > > added them to the patch system. > > > > > > I'm not sure which patches you're talking about, but discussion is > > > still ongoing, so it would be greatly premature to merge anything. > > > > This thread > > https://lore.kernel.org/all/20251110145555.2555055-1-bigeasy@linutronix.de/ > > > > and the patches are 9459/1 to 9463/1 in your patch system. They address > > other issues, not this one. > > Oh, the branch predictor issue. Yea, I'm not keen on changing that > because I'm not sure if it's correct (the knowledge for this has > long since evaporated.) There have been multiple attempts at fixing > this in the past, and I've previously pointed out problems with > them when I _did_ have the knowledge. Have you looked back in the > archives to see whether any of that feedback I've given in the past > is relevant? I dug up the emails from 2021, 2019 and you complained that I open the interrupts too early. Now I moved the invocation of hardening the branch predictor to happen before the interrupts are enabled. Based on that it should not raise to any complains. > > So Will suggested to let change the handler and handle this case. The > > other patch is avoiding handling addr > TASK_SIZE. > > Any preferences from your side? > > ... and now we have a new proposal from Linus. I'm not intending to > do anything on this new problem until the discussion calms down and > we stop getting new solutions. Okay. If we could please sort out the first part then it might be easier to move on here once the dust settled. Sebastian