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 5D195CCD1AB for ; Wed, 22 Oct 2025 09:58:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A2F028E000B; Wed, 22 Oct 2025 05:57:59 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A07028E0002; Wed, 22 Oct 2025 05:57:59 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 943FE8E000B; Wed, 22 Oct 2025 05:57:59 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 823608E0002 for ; Wed, 22 Oct 2025 05:57:59 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 0DBB4BB6AF for ; 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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761127077; 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; bh=caZZFGjSl0HauoREUr8sdpmyd8rmYIzTl3VncLuUe00=; b=CFJRL44c++W90zv/JBvcCh7L0DPn0Ne1AxHOfwRw5FtQHI36n/BsmzhsW4hGyFpAd/pztR Ys3GPK4j26tX6mLEVL8KzmSI8k2NIIx5rahT1YdIeDk9rMCHH3zGsdZBGs3h9tZGOdu1IF sB8K3YLxCmceXVN4RI6acGKMHAqg4WU= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id C6863602D7; Wed, 22 Oct 2025 09:57:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 031A3C4CEFF; Wed, 22 Oct 2025 09:57:54 +0000 (UTC) Date: Wed, 22 Oct 2025 10:57:52 +0100 From: Catalin Marinas To: Yang Shi Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, syzbot+d1974fc28545a3e6218b@syzkaller.appspotmail.com, Will Deacon , David Hildenbrand , Kefeng Wang Subject: Re: [PATCH] arm64: mte: Do not warn if the page is already tagged in copy_highpage() Message-ID: References: <20251021181353.3842660-1-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 9881820004 X-Stat-Signature: 93uhdffiqekgtod5dxiu9i99jwncpwgb X-HE-Tag: 1761127077-448506 X-HE-Meta: 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 wX92gXLl QR3iRKqTohy6SMbtD5hd/bdkYE5vLDJ7NoIw0tnID6qRyGCHXHmRXpE6CtxfUCDXm85C+Rmp52c178QJq+7cAHk9i+m/fg4+6IC+7ZLg9a42YJdjMrNj+XEIq1ysMtwgCz+Ongy9dRUE544AxBUEuQ9W3VjeKGs6EUUJVm8wUpYlO7kLT+aLj0HQYi1OnqGJZ6HrVgLwe55HR7UTI9hyIeTC6Aw== 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 Tue, Oct 21, 2025 at 12:00:04PM -0700, Yang Shi wrote: > On Tue, Oct 21, 2025 at 11:14 AM Catalin Marinas > wrote: > > The arm64 copy_highpage() assumes that the destination page is newly > > allocated and not MTE-tagged (PG_mte_tagged unset) and warns > > accordingly. However, following commit 060913999d7a ("mm: migrate: > > support poisoned recover from migrate folio"), __folio_mc_copy() is > > called before __folio_migrate_mapping(). If the latter fails (-EAGAIN), > > the copy will be done again to the same destination page. Since > > copy_highpage() already set the PG_mte_tagged flag, this second copy > > will warn. > > > > Replace the WARN_ON(page already tagged) in the arm64 copy_highpage() > > with a comment. > > > > Signed-off-by: Catalin Marinas > > Reported-by: syzbot+d1974fc28545a3e6218b@syzkaller.appspotmail.com > > Link: https://lore.kernel.org/r/68dda1ae.a00a0220.102ee.0065.GAE@google.com > > Cc: # 6.12.x > > Cc: Will Deacon > > Cc: David Hildenbrand > > Cc: Kefeng Wang > > --- > > arch/arm64/mm/copypage.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/mm/copypage.c b/arch/arm64/mm/copypage.c > > index a86c897017df..40749d0a385c 100644 > > --- a/arch/arm64/mm/copypage.c > > +++ b/arch/arm64/mm/copypage.c > > @@ -51,8 +51,13 @@ void copy_highpage(struct page *to, struct page *from) > > } > > folio_set_hugetlb_mte_tagged(dst); > > } else if (page_mte_tagged(from)) { > > - /* It's a new page, shouldn't have been tagged yet */ > > - WARN_ON_ONCE(!try_page_mte_tagging(to)); > > I think you should remove the WARN_ON_ONCE in the above hugetlb chunk > too IIUC. migrate_huge_page_move_mapping() does the similar thing. Good point. Thanks! -- Catalin