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 C760423D7C7 for ; Fri, 5 Dec 2025 07:41:15 +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=1764920475; cv=none; b=ouDj9gYbgByAiZVgpxhtDqxUlYKfFaaNDC4ZTxJbMFVa7yqYDN4zdQjhWsERHKhYXuepmeBrkVwfTTp240TJWl4HitYRShCmgk9iD45xIr9PXmNIMVxWvc8z674qcqCtDxcrcBMF3HALlcZ+/llrr3hJsBhMZu6KXDC52wIqshA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764920475; c=relaxed/simple; bh=JNIyYc/7yP1M4TvP6ofkJrx/viH5F1sL/Inc63ohX0Q=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=pM4yBJFTq+kuxuc/LCTl5u8/00Y1jqlmrv1PYshQMjL93vk0jvgcMxflVLcchZSdWodPhF+M1sSlcNNTp5v2jUbuD7IOn+4Ch2EmQY1VJYTsKf+UdKOsD1ATT26nH1ye+fvs3W31qv5iShuWIsvBLemCl1Z5epqeUwzWLK/Rsrk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=NV3YL29e; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="NV3YL29e" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5F3D0C113D0; Fri, 5 Dec 2025 07:41:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764920474; bh=JNIyYc/7yP1M4TvP6ofkJrx/viH5F1sL/Inc63ohX0Q=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=NV3YL29eliNneTWlA8ePGTMtSS/n+uTN5J5jvZlhhbhGID3WpRpsny7Z93D360p8z CcD2Jpu0zNvCPb9wT5veXmNC3bd1s1KSysRMJEunjTUGnYrmaFBFaE2UG4qBOFZHYt IentCY9LrG+gTxkx+aGEz8vL6BwXVoyc6pTklOkA98XKMXmy2ONe2ESzjdrXoEwSW7 9p7mC8TL2SZ6Ob8vUY5B6UT0OIdXu0pG1+/F/uYupAeHJaiyZGsxI7HtgMMT7YGq6E cP1MUhOOe5SLYbudGokd7AeJKtjSzSj50EYV7+Vd3YPBiPkwLBJ0uqcWjvirqmQi0z 6Xs4n124j53Tg== Message-ID: <057ff845-6ab3-46a2-82df-067c25bef56e@kernel.org> Date: Fri, 5 Dec 2025 08:41:07 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] Revert "mm: fix MAX_FOLIO_ORDER on powerpc configs with hugetlb" To: "David Hildenbrand (Red Hat)" , Mike Rapoport , Andrew Morton Cc: Shuah Khan , maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, surenb@google.com, mhocko@suse.com, masahiroy@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds References: <20251204023358.54107-1-skhan@linuxfoundation.org> <20251204135746.6d291cc861b4507b1fe95aaa@linux-foundation.org> Content-Language: fr-FR From: "Christophe Leroy (CS GROUP)" In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 05/12/2025 à 08:05, David Hildenbrand (Red Hat) a écrit : >>> 39231e8d6ba7 simply shuffles ifdefs and Kconfig items, so I assume it >>> exposed a pre-existing bug. >>> >>> Reverting 39231e8d6ba7 will re-hide that bug. >> >> Shuah confirmed that the bugs were on v6.18-rc6 and they were fixed in >> 6.18 [1]. >> >> I verified that reverting 39231e8d6ba7 from v6.18-rc6 does not solve >> anything, but applying 5bebe8de19264 does [2]. >> > > Thanks! > >> So reverting 39231e8d6ba7 does not change anything and there is no bug it >> hides. The bug was introduced by adfb6609c680 ("mm/huge_memory: >> initialise >> the tags of the huge zero folio"), was fixed by 5bebe8de1926 >> ("mm/huge_memory: Fix initialization of huge zero folio") ... >> >>> And that isn't a bad thing.  If we re-hide the bug in 6.18.x and in >>> mainline then that relieves the people who are hitting this and it >>> takes the pressure off David, Mike and yourself to get the underlying >>> bug fixed in a hurry. >>> >>> So I think I'll queue this as a hotfix, plan to send it Linuswards in a >>> couple of days. >>> >>> Or Linus may choose to apply it directly or to do a local revert of >>> 39231e8d6ba7.  But I don't see how a local revert will get communicated >>> to the 6.18.x maintainers. >>> >>> David, Linus, opinions please? >>> >>>> Signed-off-by: Shuah Khan >>> >>> Let's have a cc:stable here, just to be sure. >> >> ... and we can skip all this hassle. > > Yes. > > Thinking about reverting arbitrary commits after Shuah clearly tested > something wrong is completely unreasonable. > That irrelevant revert has already been applied on mm-hotfixes-unstable, see https://lore.kernel.org/all/20251204215938.750D3C4CEFB@smtp.kernel.org/ Andrew, could you please drop it ? Thanks Christophe