From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792743601; b=0sIrf3q7Fuf6oOYAXvQXQQ5bL8VuHIbOR/w/rgU5H++5egKa3pInkwxGys5JgJvQ7C+S ZywPvdbW5pHiE/ixXoz7uuvhdInCEzXTcdgdGHf7TDToiXpr3JvawNQVtmKyycnq5BeU2 /HbRh3f73o2/HsQ1is52DtYXLuN5XjBhFMVDv0hzlUkHKgugvJ3X5RXOfzBmvt2uZD8xw qDL5DZlB/HzXgbxchyM3I1lGDywS526I4ujIX4X0wGbkdwbxa3uSa9tHLV6ndbLofqJLR evQ9gVcc0V2z6VxhocM04MPCyZB+K9o9EnbbWwvrpkMU/WVEZ1FX1jX4jXly0/i1kBQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792743601; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=w+uZcRKsV5h7EXsxKjGUwOGNuNwl+VfHuYMNxjipb3o=; b=fk16iKPH/DeZCP4m77TpFsSEKexgEMWyKCemtcCUIDYCERwMckY0nj5o8Z2/JTehu1qg T8VUderA5vyW5knJULcw/Js7faSDgdNdZiWMr3V1Y3vCPA7jKFTgEyai6xPJ6kizEo1iH SWnQ4IudOTYPHBG+cT41I7QaUOFcc/AUL/o5JAW62vU1njqTCus4HsbLnivsUMolbAgzy HNUZuQCrHsiv9kdGmsN6GX4Atxb4P+oe5iVfUwlOZoF6/cEBf8ZbY14plaVSiIgI3Tpyw GK5mFLYLiLoCSr+NGhAf4r1UnzT9cyS+URJzMJi+bO2Mbjg+j02VLk4nqaiknEGOy7w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="hC/L1MQ7"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 731C9606A31A for ; Fri, 23 Oct 2026 08:20:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=hC/L1MQ7 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 739661F01825; Fri, 23 Oct 2026 08:19:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792743601; bh=w+uZcRKsV5h7EXsxKjGUwOGNuNwl+VfHuYMNxjipb3o=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=hC/L1MQ7M1aO8VZ1NXHGDX9iszEeVlPNaBbhvunGdg6YNBPw8L9Mzspsy+ar1087V HmI/6gwOaEEx2Kl+YPdzPJZt36tE6xVjAKtEEucZ7Tmsn7YBZNJaj04xcEv4cCsdqT vU7oHMiREtChPgWu+glIZCkuwamoY67wWqaJ4q9USt5OWNPUp4zvOLwDRVfw9EwNbv Yps23mfbB9M/jv+2MAx6cHKMEPuPmw0tRfdrDDKlr6q+B852EUofQvXDP6WhhStfy7 4OfSVa4tbqcjD2OakjYBIpsekvIf0gLa5MNL9qrnUPH3S5/pgVH3oTl4hj32sCWyr3 teIHgcWiNO/Lg== Date: Fri, 23 Oct 2026 09:19:55 +0100 From: "Lorenzo Stoakes (ARM)" To: "Vlastimil Babka (SUSE)" Cc: Luiz Capitulino , Andrew Morton , "Liam R. Howlett" , Jann Horn , Pedro Falcato , David Hildenbrand , Jakub Matena , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [REGRESSION] mremap() fails VMA expansion when VM_MIXEDMAP is set Message-ID: References: <20261023023106.515365-1-luizcap@redhat.com> <8c53e58c-f7d2-4e98-8d03-7ff1163c1159@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8c53e58c-f7d2-4e98-8d03-7ff1163c1159@kernel.org> On Fri, Oct 23, 2026 at 09:16:12AM +0200, Vlastimil Babka (SUSE) wrote: > On 10/23/26 04:31, Luiz Capitulino wrote: > > This regression was introduced in v6.1 by commit ca3d76b0aa80 ("mm: add merging > > after mremap resize"). This commit changed mremap() to use vma_merge() instead > > of vma_adjust() for the expansion case. However, vma_merge() returns NULL for > > a VMA that has any of the VM_SPECIAL flags set. > > Hi, > > 6.1 was a rather long time ago. How was it discovered just now? I.e. what > use case broke by the change and prompted creating the reproducer? > > Vlastimil > Thanks, Thanks, I have the same questions :) Do always include that kind of information and whether it was an LLM-discovered thing or whether you had an actual workload that was impacted, etc. -- Cheers, Lorenzo