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 E98A32F12B3 for ; Thu, 4 Dec 2025 22:12:14 +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=1764886335; cv=none; b=SvD6y7yF32+quy1Qb3OAigK14qR1gzYTBCiPVkirVSj4O9kT+BlBuwv8fOA5V/1yRtRbGYMio4xv364ClkkebDJoUMizKtfL1ONAbQbyyqwSvg22iC8fypp5p1p0hCk/mx1pPyL5vawkNrLPPFcduH0X8b/XmHI12FyFrqBAWfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764886335; c=relaxed/simple; bh=ubLwl5+CgitwUP+ApeREHrjaIt9HSqJeqF496mwgdzU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Sh015xRGFGsfgL67oZ4tC/jYsnEoPF2xpJYTWUtxYEaXt8l7PWGJU/lDLgFOk7tAhsM1rwmrpV2X11kTR0SYrY9aOzhEd6Np72RoBU4UuKYDtkXilqk+naIUB8QXKC8k9NlH6L4W1EPKLBHFUvw9EIzsmm0A1qwAOnkgi7wQMz0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IAzw1OUH; 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="IAzw1OUH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 17168C113D0; Thu, 4 Dec 2025 22:12:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764886334; bh=ubLwl5+CgitwUP+ApeREHrjaIt9HSqJeqF496mwgdzU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=IAzw1OUHYgUWBP5mdicRgkXgo68l062ZNu3AOYLPZXPFoAEtFD1fhoIwy2uRycPZY 96wUtdi8CnoG3eZUHlVW37tSpWW6YJl6D8dn2jqFgwB+4tDZ9jzkbADts5LgJ94LKX 9u5T6aFzJsO61OIQXrXQfZqjRX+qVBy1/I2z7Vxe1H/OExo7dhtAtfnEkgg69CRkGk 4VGCkxc6Zf/JDHGdwrUYFCpVp6pb3dBU9b5LZBoBse7FvyGmKojZRmzdvvgpvpiMpb mF5For1ffogsUFSD6jGYvu7hFZWxq0+HwB5Y85vSctNh9hlsn5Ox6Mku0zKBmni9Mb F1Twn2KYLcVzg== Message-ID: Date: Thu, 4 Dec 2025 23:12:06 +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: Andrew Morton , Shuah Khan Cc: maddy@linux.ibm.com, mpe@ellerman.id.au, npiggin@gmail.com, christophe.leroy@csgroup.eu, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, 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> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <20251204135746.6d291cc861b4507b1fe95aaa@linux-foundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 12/4/25 22:57, Andrew Morton wrote: > On Wed, 3 Dec 2025 19:33:56 -0700 Shuah Khan wrote: > >> This reverts commit 39231e8d6ba7f794b566fd91ebd88c0834a23b98. >> >> Enabling HAVE_GIGANTIC_FOLIOS broke kernel build and git clone on two >> systems. git fetch-pack fails when cloning large repos and make hangs >> or errors out of Makefile.build with Error: 139. These failures are >> random with git clone failing after fetching 1% of the objects, and >> make hangs while compiling random files. >> >> The blow is is one of the git clone failures: >> >> git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux_6.19 >> Cloning into 'linux_6.19'... >> remote: Enumerating objects: 11173575, done. >> remote: Counting objects: 100% (785/785), done. >> remote: Compressing objects: 100% (373/373), done. >> remote: Total 11173575 (delta 534), reused 505 (delta 411), pack-reused 11172790 (from 1) >> Receiving objects: 100% (11173575/11173575), 3.00 GiB | 7.08 MiB/s, done. >> Resolving deltas: 100% (9195212/9195212), done. >> fatal: did not receive expected object 0002003e951b5057c16de5a39140abcbf6e44e50 >> fatal: fetch-pack: invalid index-pack output > > 39231e8d6ba7 simply shuffles ifdefs and Kconfig items, so I assume it > exposed a pre-existing bug. > > Reverting 39231e8d6ba7 will re-hide that bug. > > 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? I have so far no indication that this patch here would change anything relevant to the problem we are seeing, all it does is changing MAX_FOLIO_ORDER that does not affect any logic we would really care about here (safety checks and snapshot_page()). Can we please wait a bit so we have confirmation that it's not a leftover from the huge-zero-folio thingy or something different? As Mike reports, he found ways to reproduce something similar even with 39231e8d6ba7 reverted. -- Cheers David