From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1659342AA6 for ; Thu, 13 Nov 2025 23:08:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763075293; cv=none; b=aUwkqxx4Or+dSt8POBpXF4e1CSrj0O9ds+0yEYGBeZ86b64ocbya5q7gYiSxg8v1MM6+6z5koLNB0ibVXlCauBXN3ROoI46uAdX2+Ml7Fg6EgcivfasdAig4KTndfkzorXyWKeJROojMI3dkcxCd5woy1nDL+wbkb6lWujNmtgI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763075293; c=relaxed/simple; bh=2wvqa/HMit8pu0w6FTlokZJLz41y4povJ4/y0QBe68k=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=XWpNLzOaNdc6/j+Q3t0g4GSP8sOuOO1efYiTZh1mdqXe6jA5nCpak9OtvIWcmi3vL3jvF54MQMoBuU17KG10YgqUey2mxGs3SwP9sdERULmiT7oYciFUcakzSO/+rodDf7j3JLw+a9AFKCQ+A0DtfY/A25F2agf+C98ivJ6UbRM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=2V0F07x9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="2V0F07x9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8BBCC4CEF7; Thu, 13 Nov 2025 23:08:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1763075292; bh=2wvqa/HMit8pu0w6FTlokZJLz41y4povJ4/y0QBe68k=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=2V0F07x99YAiF85Sx7V1XWStJGYjslzh/mevzVy07rE/VuwVdP2ufpoJPqaCRs6Bk EN1xQs77scGH//E4rc4vilieGQQUwW44aylFuMIPg20ze2nBtAe21fLQKQpDoPL5Sh JXD/31O+MxpDt1neiBxsZiTtccuDP2TnCwhvKE60= Date: Thu, 13 Nov 2025 15:08:11 -0800 From: Andrew Morton To: Balbir Singh Cc: "David Hildenbrand (Red Hat)" , Lorenzo Stoakes , linux-kernel@vger.kernel.org, linux-mm@kvack.org, dri-devel@lists.freedesktop.org, Zi Yan , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Oscar Salvador , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lyude Paul , Danilo Krummrich , David Airlie , Simona Vetter , Ralph Campbell , Mika =?ISO-8859-1?Q?Penttil=E4?= , Matthew Brost , Francois Dugast Subject: Re: [PATCH] mm/huge_memory: fix override of entry in remove_migration_pmd Message-Id: <20251113150811.081a6dbdcca8b5c474d6e399@linux-foundation.org> In-Reply-To: <5092cfb0-ad25-40ff-9a07-3de86d37665f@nvidia.com> References: <20251113051352.1753714-1-balbirs@nvidia.com> <5092cfb0-ad25-40ff-9a07-3de86d37665f@nvidia.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Fri, 14 Nov 2025 07:55:29 +1100 Balbir Singh wrote: > >> THe logic LGTM but we don't want to have a bisect hazard here by having the bug > >> introduced earlier then resolved here. > > > > Exactly. > > > > The hazard is a VM_WARN_ON() that checks for is_migration_entry() in the > call to softleaf_is_migration_young(). I am happy to go down that path, > let me send out the fixups, it felt weird to break the rebase, but I > am sure Andrew has a better way of dealing with this stuff. Yes, please tell us which patch introduced the issue then send a fix for that patch. We can figure out the softleaf changes later. (Which this patch provides anyway). Also, confusing that the changelog says "The softleaf changes exposed a BUG in remove_rmap_pmd()" but it's remove_migration_pmd() that gets altered. Please expand and clarify?