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Mon, 22 Dec 2025 10:54:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766400892; bh=cv/VTMXLxul+HjudSJW7wkMxfJdfBr+el6AQMlItv9w=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TBbcOWnSr19MwF0MKrCb2IoabYD0Nb+Hare+gEpTLzqusRx2+g7sBBoVWN7mXfVuZ 9g48PR844JLrnIVBXNJDcPRzZ9OqZquI7XiHNGeRwHRykZYpEycTOUpmGN0z4nW/2x exNm6rPf3N4LEfbJUmfd492tMzcaecLPdXqfDuC4XviG8bw0zrKfc340q+uV2v7A31 tSGddRTWmUAG4XhmWs/NugkfoosrV9ks7Kz30Zoom9Se8/nzViTi1v4hjixSRy25gU EU0bg8YbcDJPHiMekaav/bto5jUZ768ihhxepiBF9REEAyupmmRO5IMAzEtlO7J7ps 8hPuYpgjOVq+g== Message-ID: Date: Mon, 22 Dec 2025 11:54:46 +0100 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 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6] mm/hugetlb: ignore hugepage kernel args if hugepages are unsupported To: "David Hildenbrand (Red Hat)" , Sourabh Jain , "Ritesh Harjani (IBM)" , Andrew Morton Cc: Borislav Petkov , Heiko Carstens , Ingo Molnar , Madhavan Srinivasan , Michael Ellerman , Muchun Song , Oscar Salvador , Thomas Gleixner , Vasily Gorbik , linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, x86@kernel.org, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org References: <20251221053611.441251-1-sourabhjain@linux.ibm.com> <87a4zcml36.ritesh.list@gmail.com> <655cc605-2ce1-4ccb-8cc0-a0a31a9c89fd@kernel.org> <87fr93ky5i.ritesh.list@gmail.com> <16fef7a5-6853-4a6f-8d27-e005fa351eb7@linux.ibm.com> <051628be-ed70-4a56-8704-f2b8cdea1984@kernel.org> Content-Language: fr-FR From: "Christophe Leroy (CS GROUP)" In-Reply-To: <051628be-ed70-4a56-8704-f2b8cdea1984@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Le 22/12/2025 à 11:28, David Hildenbrand (Red Hat) a écrit : > On 12/22/25 06:57, Sourabh Jain wrote: >> >> >> On 22/12/25 08:42, Ritesh Harjani (IBM) wrote: >>> "David Hildenbrand (Red Hat)" writes: >>> >>>>> Coming back to the fixes tag. I did mention a bit of a history [2] of >>>>> whatever I could find while reviewing this patch. I am not sure >>>>> whether >>>>> you have looked into the links shared in that email or not. Here [2]: >>>>> >>>>> [2]: https://eur01.safelinks.protection.outlook.com/? >>>>> url=https%3A%2F%2Flore.kernel.org%2Flinuxppc- >>>>> dev%2F875xa3ksz9.ritesh.list%40gmail.com%2F&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cfe40f4881e8441ab3ebf08de4144e747%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639019961377096292%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=Dnvzy5kJ%2ByF9GJjIw%2B12FTjaVgeAM2gA9g7hsYl7Qok%3D&reserved=0 >>>>> >>>>> Where I am coming from is.. The current patch is acutally a partial >>>>> revert of the patch mentioned in the fixes tag. That means if this >>>>> patch >>>>> gets applied to the older stable kernels, it would end up bringing the >>>>> same problem back, which the "Fixes" tagged patch is fixing in the 1st >>>>> place, isnt' it? See this discussion [3]... >>>>> >>>>> [3]: https://eur01.safelinks.protection.outlook.com/? >>>>> url=https%3A%2F%2Flore.kernel.org%2Fall%2Fb1f04f9f-fa46- >>>>> c2a0-7693-4a0679d2a1ee%40oracle.com%2FT%2F%23m0eee87b458d93559426b8b0e78dc6ebcd26ad3ae&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cfe40f4881e8441ab3ebf08de4144e747%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639019961377117150%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=bOO7FGN4jAtX3jjBnJVpSurmM9rGmz8vIs1iGtbm1gU%3D&reserved=0 >>>>> >>>>> ... So, IMO - the right fixes tag, if we have to add, it should be the >>>>> patch which moved the hpage_shift initialization to happen early >>>>> i.e. in >>>>> mmu_early_init_devtree. That would be this patch [4]: >>>>> >>>>> [4]: https://eur01.safelinks.protection.outlook.com/? >>>>> url=https%3A%2F%2Fgit.kernel.org%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Ftorvalds%2Flinux.git%2Fcommit%2F%3Fid%3D2354ad252b66695be02f4acd18e37bf6264f0464&data=05%7C02%7Cchristophe.leroy%40csgroup.eu%7Cfe40f4881e8441ab3ebf08de4144e747%7C8b87af7d86474dc78df45f69a2011bb5%7C0%7C0%7C639019961377133860%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=0yTuECy%2BBGDLiSNYuqYH9xGBOSxiRLxAtW%2FWTQU%2FB%2BA%3D&reserved=0 >>>>> >>>>> Now, it's not really that the patch [4] had any issue as such. But it >>>>> seems like, that the current fix can only be applied after patch >>>>> [4] is >>>>> taken. >>>>> >>>>> Do we agree? >>>> I think we should document all that in the cover letter, an describe >>>> that this partial revert is only possible after [4], >>> Yes, I agree. Let's add the above details in the commit msg. >>> >>>> and that that must >>>> be considered when attempting any kind of stable backports. >>> Sure. I would prefer if we change the Fixes tag to the one which I >>> pointed in above [4] (with explaination in the commit msg). However I am >>> still ok if we would like to retain the existing fixes tag and show [4] >>> as a dependency. >> >> I think we should keep the current Fixes tag with an explanation for >> dependency >> on [1] in the commit message. >> >> Would anyone have a different view? > > Whatever introduced the issue should be called out in the Fixes tag; if > there are dependencies for the fix through other patches that were > already merged, that can be documented in the patch description > (relevant for stable or distro backports only). > We can also use the Depends-on: tag, see for exemple commit 9517b82d8d42 ("nbd: defer config put in recv_work"): Reported-by: syzbot+56fbf4c7ddf65e95c7cc@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/6907edce.a70a0220.37351b.0014.GAE@google.com/T/ Fixes: 87aac3a80af5 ("nbd: make the config put is called before the notifying the waiter") Depends-on: e2daec488c57 ("nbd: Fix hungtask when nbd_config_put") Signed-off-by: Zheng Qixing Signed-off-by: Jens Axboe Christophe