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Fri, 5 Dec 2025 07:01:33 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 915C5C4CEF1; Fri, 5 Dec 2025 07:01:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764918093; bh=fBB52+FpmiRjld7TBCQI6MHpA8C2/HNb3RkNEkzbihM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=GgPY+DoNZhiHH3jItOJ3AYgP5WTSiMtpLCZSWOmEK7RicGrrRqMeWPT8B4Vl1nQCx JYntcXZRE3K6JabczWDsVjntVOkYV8FEdRNFsepd3p56NPUo7JqQMmI582XOmaBMpJ 87Y3iQUR+WG5fLuEHFeLat/QHKBLHKVuRS/ElFoCFupAhWni4rxoIHbZ93xDq5Y2yA 89Gm9E2xFp/Y5EnWo0Jv26IpBbCweuq/Cl/aZv2HztATkK5E5lCifF+oU9qvZO0/qo JYHrYFMDtgc5Ytnto1g8r6P3+PtBC0ECvHdcFkCsnFMi0wRKVodMizWY0Y2vj09Je6 XKldPNeaY+qgQ== Date: Fri, 5 Dec 2025 09:01:24 +0200 From: Mike Rapoport To: Andrew Morton Cc: Shuah Khan , david@kernel.org, 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, 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 Subject: Re: [PATCH] Revert "mm: fix MAX_FOLIO_ORDER on powerpc configs with hugetlb" Message-ID: References: <20251204023358.54107-1-skhan@linuxfoundation.org> <20251204135746.6d291cc861b4507b1fe95aaa@linux-foundation.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251204135746.6d291cc861b4507b1fe95aaa@linux-foundation.org> On Thu, Dec 04, 2025 at 01:57:46PM -0800, 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. 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]. 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. [1] https://lore.kernel.org/all/317deba2-e560-44ed-a9f7-3c6fdc446b6d@linuxfoundation.org [2] https://lore.kernel.org/linux-mm/aTKAo7JgBX0X_pBl@kernel.org -- Sincerely yours, Mike.