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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 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 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: AFE121C000D X-Stat-Signature: 6g8w51siy3rw77a9qqauxb1owqzs1toq X-Rspam-User: X-HE-Tag: 1764920475-422942 X-HE-Meta: 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 z1TeEzFs obSl0lo3KfWDNZRE= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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