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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-Stat-Signature: wxnof3ybbtst16ub1w9fk4zhd3ffroe6 X-Rspam-User: X-Rspamd-Queue-Id: B60D8C000A X-Rspamd-Server: rspam09 X-HE-Tag: 1764501612-585926 X-HE-Meta: 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 e5j9FmBi /u2RLniaMwLM6/6M8slTBO3wIV5iR7X+pXo4zuf7Vj5VTyyOCvLiyvELz1n5mgyGs0UDm6xoN1dCKQiLofrxIWDD/FQo7IPOQhftSODq3aaDsUnv2uNIaS4pqSs5TzVA/SuwaBQWCpn90hzT0Ma1CfBGDp8i8vO3QWe+nMqupBQoQxjAWevbbd/Aal3FOzdqJt+pHJZMukkzPNsi7Hi6N1+nX3D0kv4WiA7gYRDLzt7gvw4+cXT6tUV6LcgjAi5yxS3EhONFU5owCqP8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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