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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id CE5A3C61DB9 for ; Tue, 25 Aug 2026 20:06:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C81726B0095; Tue, 25 Aug 2026 16:06:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C330A6B0096; Tue, 25 Aug 2026 16:06:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B489B6B0098; Tue, 25 Aug 2026 16:06:05 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 933AE6B0095 for ; Tue, 25 Aug 2026 16:06:05 -0400 (EDT) Received: from smtpin17.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 186E180145 for ; Tue, 25 Aug 2026 20:06:05 +0000 (UTC) X-FDA: 85140873090.17.DF16E28 Received: from mta1.migadu.com (out-79.mta1.migadu.com [95.215.58.79]) by imf30.hostedemail.com (Postfix) with ESMTP id C381B8000F for ; Tue, 25 Aug 2026 20:06:02 +0000 (UTC) Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=F9U2jhQT; spf=pass (imf30.hostedemail.com: domain of atish.patra@linux.dev designates 95.215.58.79 as permitted sender) smtp.mailfrom=atish.patra@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1787688363; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=XbjAz7qal9P/BA1hWjjA2A6ymhlraYwWduqNMnGPNfM=; b=3upO7hUknUFlW/IWLhXkVUyj6X5+vuHnVUW0G5v33ynnKbriBPj6AGg12FtCV7wYGgvhIW Ip/Brbd5fdIJiBV9Pmhhl5xgcQP/WikjfhbYLZIKRhWsINIUyM6TcB8x+OxQFxpz2th6UK HosNaIlNlgWwW7ly0MoL4t3vBABH6D4= ARC-Authentication-Results: i=1; imf30.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=F9U2jhQT; spf=pass (imf30.hostedemail.com: domain of atish.patra@linux.dev designates 95.215.58.79 as permitted sender) smtp.mailfrom=atish.patra@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1787688363; b=OOVIywmaWadwh6jC4Jjzinw4qorJtiwrn1u+TgQMzcexFAPnEjxoBxgpzjC4FIapPwkwma moaG8Lqb5ips5l9eA/HM9rhDt+9LWUWBzJvnuvlDg4i5rxyw7GxvcaQtQojK/jHvBQCaQw lObsU6IqASd654Gx85EgmPLS1N/r/aY= X-Envelope-To: linux-mm@kvack.org DKIM-Signature: a=rsa-sha256; bh=XbjAz7qal9P/BA1hWjjA2A6ymhlraYwWduqNMnGPNfM=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787688360; v=1; x=1788293160; b=F9U2jhQTev4uP28NPHwP7qg9cVC0YxNRBdvTHtPArQ0MbbPTaCi1UpBz/QCeF39oIA6JP0zR q3SQEbybvl1aBmhYFEkjqvfjnKayhLneiA5C1OiukTjpvXQYs2TOhcIzmpdeENdoY+k20HLtQLt twS2PFIjdz9R5b54EltRitKQ= X-Envelope-To: linux-mm@kvack.org Received: from [IPV6:2a03:83e0:1156:1:10b7:9472:4142:b7b7] (2620:10d:c090:500::7:759c) by smtp.migadu.com with ESMTPS id 9b0c0d836eb66a38; Tue, 25 Aug 2026 20:05:50 +0000 X-Mizu-Trace-ID: 9b0c0d836eb66a38 X-Migadu-Flow: FLOW_OUT Message-ID: Date: Tue, 25 Aug 2026 13:05:37 -0700 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/5] x86/mm/pat: CPA fixes To: "Lorenzo Stoakes (ARM)" Cc: Mike Rapoport , Dave Hansen , Andrew Morton , Andy Lutomirski , Borislav Petkov , David CARLIER , David Hildenbrand , Ingo Molnar , Jason Gunthorpe , Jiri Slaby , Juergen Gross , Kevin Tian , Kiryl Shutsemau , "Liam R. Howlett" , Lu Baolu , Nikunj A Dadhania , Pedro Falcato , "H. Peter Anvin" , Peter Zijlstra , Shakeel Butt , Steffen Dirkwinkel , Suren Baghdasaryan , Thomas Gleixner , Toshi Kani , Vishal Moola , Vlastimil Babka , Will Deacon , iommu@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, syzbot@syzkaller.appspotmail.com, x86@kernel.org References: <20260813-cpa-fixes-v2-0-39b4ff90f91d@kernel.org> <556337a8-5e2b-45fe-a1ba-90a90c1f3c4d@linux.dev> Content-Language: en-US From: Atish Patra In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Stat-Signature: o51jmdfct9613hf66f1mtbd8bc187h7k X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: C381B8000F X-Rspam-User: X-HE-Tag: 1787688362-550025 X-HE-Meta: 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 3o9UTN1L KxRFXvdY8l7XOdqwer5f1gAfI/5f4XWZA9QW7qawMNqcbBhEr56XHCv4jfSdYxFDpol6W9IYhEGK7futJoPvEPom9pBiYpgMOy7bMqWsQ/DtzqKjmMO02gOxeSBbYc79Q6uTi5fwkdk0T+tYT4ZWXONnUTQKftsfmPFF7iy1x/2wLuFNCbZtvjPdS3M6fZhASDUnDaDAjaEflQJU1RPkDxPIu9RUfyCNb+iMxb9jCxtDCyTqBfGb/RuQFIov470g6Amc166Y6RfHkdXF1DJ0MbohgKLuNaFEn9eMCaHQ9TDCoNDCE4JKtrOQRdl9xjxOuOfRg4FMCqqZTSZ6yXks+BAhtTBdDjsTcc+UkGyf9BQWTFHLOAcHgwvIW8B4lZ57cxBUY+EGdTcAuup7byNHg8xJxRLBwYJF/zGOFwNZXC4ie6Wc+KlDeW7ooig== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/25/26 12:31 AM, Lorenzo Stoakes (ARM) wrote: > On Tue, Aug 25, 2026 at 12:12:32AM -0700, Atish Patra wrote: >> Reproduced and verified this series (patches 1-3) on 4vcpu guest running two different kernels >> 1. mainline (commit: 77ae27fd98f3) >> 2. Ubuntu Resolute 7.0.0-26 (production kernel hitting the issue in a VM) >> >> The Reproducer consisted of >> 1. A debug patch a cmdline-gated stall between the two *pmd reads in vmalloc_to_page() >> 2. One taskset-pinned insmod/rmmod worker per module over stock cfg80211/dummy/veth modules >> >> With the above reproducer, both BUG within seconds in unpatched kernel. >> 1. Resolute in 0.71s at alternative.c:2564 (BUG_ON(!pages[0] ...), RAX=0) >> 2. mainline at alternative.c:2473 (BUG_ON(memcmp(addr, src, len))). >> >> With patches 1-3: zero splats across 10 runs each (600s/11,378 module load/unload cycles on mainline and 1200s/55,980 module load/unload cycles on Resolute). > Amazing, thanks! > >> >> Tested-by: Atish Patra > I guess should be applied to patches 1-3 only strictly? Or perhaps 3/5? Yes. 1-3 sounds good. >>> -- >>> Sincerely yours, >>> Mike. >>> > -- > Cheers, Lorenzo