From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 347A83DBD54 for ; Mon, 29 Jun 2026 10:21:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782728483; cv=none; b=Dch2VFDxvlAAHR+GoZ90wlQK88Aup4rvq7lBQle8H5Y3EqL0diuUeXvl40xdO8PraNCqMyceLAd5ZkjsyE+k1wyDAN9P02eZXb5xPwrM4UkzOfmUt5Ll6b31dIX3k9qiVIFm12hQVh2XBjv++n5N4CVNRUs4jU/TY5qv6uYiC5Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782728483; c=relaxed/simple; bh=mt8L6LnpYSOjF98vPFSM5eGARRpc2PVG3lnGf28XSEI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=n6EuUb11YdSH1P4rGps+guUeX5iUJINaSLYU9kR6NPbDzm7417vqgu8v+SCvZ3aCiaEz9XCxTyFAophuHdsnRQINtE3pWyW7q7WfXctYT5jrSoQZ9JRmwXGumaJY0ZmtlY9peFut4GdYMnvNQ2Aq0UQ8VP/st2cVnH48D9+j7sA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=k4VqO4OP; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="k4VqO4OP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 78BD21F000E9; Mon, 29 Jun 2026 10:21:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782728480; bh=hWacwzXDsthaKuP5l9YfT3wOuzUJwz+T9Kp6WoULqsg=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=k4VqO4OPJ1P0VvsP9GW4oTWLcs8PBpWPWCTU+JUJEjwiSGou7TB/CSY1pd/QfM0Z6 V+eJAqwcid7N8P4lnv+QbGlS5sVkRfVSgcGwfFsJjHIPvX2TUGzYXYufY0VC467/8i +GyGXkc2NOd97DZDMCWtvUcpj2jbJI0SWw7N7/K6ZChB5mhILggGHXx+xd6OCOOUVd S43lV0tvGH4n5XkOMuff93KHY0AFMdZ5gDjvitOEmzUEL+EjsUZSkG+I4F7AZpAFe9 zEntDDN2jVfGNrCexLn2MZrL7QzkLgiMqrVBmMQ2fZLhci8b5/YTQTC8H78TvZJqnG xLGWdxP6ETgaA== Date: Mon, 29 Jun 2026 11:21:10 +0100 From: Lorenzo Stoakes To: Andrew Morton Cc: Oscar Salvador , Dave Hansen , Karsten Desler , Muchun Song , David Hildenbrand , Vlastimil Babka , "Liam R . Howlett" , Andreas Larsson , "David S . Miller" , Huacai Chen , Alexander Gordeev , Gerald Schaefer , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 0/8] Stop special-casing hugetlb mappings in get_unmapped_area Message-ID: References: <20260606035003.529685-1-osalvador@suse.de> <20260627235512.787d09b15b3d2ff9441e604a@linux-foundation.org> 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-Disposition: inline In-Reply-To: <20260627235512.787d09b15b3d2ff9441e604a@linux-foundation.org> On Sat, Jun 27, 2026 at 11:55:12PM -0700, Andrew Morton wrote: > On Sat, 6 Jun 2026 05:49:55 +0200 Oscar Salvador wrote: > > > A regression was reported on AMD 15h Family for hugetlb mappings when 'align_va_addr' > > is set [1]. > > It would be helpful to say right here that this regression results in a > runtime BUG(). Helps get attention ;) > > > Historically, for hugetlb mappings we always ignored 'align_offset' in get_unmapped_area > > functions, but after commit 7bd3f1e1a9ae ("mm: make hugetlb mappings go through > > mm_get_unmapped_area_vmflags") that was no longer the case for x86. > > > > While we could fix that by work it around in x86 code, the truth is that the current > > functioning of hugetlb mappings with get_unmapped_area functions is a bit clumsy, and > > we can do better. > > This patchset aims at two things: > > > > 1) Fix regression reported in [1] > > 2) Stop special-casing hugetlb mappings in get_unmapped_area functions > > OK, so the offending commit was about 1.5 years ago. > > Do we want to fix -stable kernels? If so, can we start out with > something minimal for backporting? And narrow down its Fixes:? > > The series was sent at an awkward time in the -rc cycle, which perhaps > explains the lack of feedback. I suggest a refresh/retest/resend to > help bring people up to speed. Yes please rebase + resend :) > > Sashiko has quite a lot to say - I hope some of it is useful? > https://sashiko.dev/#/patchset/20260606035003.529685-1-osalvador@suse.de > Cheers, Lorenzo