From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 831B2272E6E; Sun, 30 Nov 2025 11:20:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764501614; cv=none; b=cn4W8l9JGkIrxxs2zNmQv0zZZvxBvSgwNel4nqRInZVYigpoSVUdTKDLnm7HpgHsof9BezA/qT9X4RGEMgV4quLJRlssoJdl3/cgd/ybI/wr9kq15XW9XitHkjAriEz5M+ve3yPo91XwSmgcHp/yRfUpeAAoB1yHoTwQfIDp/S4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764501614; c=relaxed/simple; bh=5GukvJtRxSI4nNFN8ne4cRSKijLmtlAAoxwznQa8t3w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=RQ+byOb6vidfq09hKWHGbD8HCjlMDs9xc0M81DEZKmn+vZVy2aJeB4DR8xXGaVEmUqMyvVveGX1QoWE7Q7QGrGyX7q5bfxkBng+Vzy2GmYb6WU8EKwg+18geUj5AVafNQF6wqno2Jqwnu/7xIxeEHFzQvzUYCOcn1ZO+Jl0Og8Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=H/O9ZzYi; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=8RrraBCZ; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="H/O9ZzYi"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="8RrraBCZ" 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> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: 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