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b=H2AL5RTjeaU1UGTpU2IxtXECuNad5hjA0WDx9Xhe/P6rqCiHdgmNce0375QgW3XmY VfJaaiAUrZoXhx89CXUQYijFf3EIRwZxRDxgsrosd7Wwpkmsws08C0pZD8o1+p1RdF s1kmLFOaNFl/kYW26LyfCuTjAK5WTgOw+FAXpPs4= Date: Thu, 27 Aug 2026 22:22:52 -0700 From: Andrew Morton To: Longlong Xia Cc: muchun.song@linux.dev, osalvador@suse.de, david@kernel.org, mike.kravetz@oracle.com, mhocko@suse.com, linmiaohe@huawei.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, xialonglong@kylinos.cn Subject: Re: [PATCH v2 1/2] mm/hugetlb: do not dissolve gigantic pages without runtime support Message-Id: <20260827222252.13fc8852f4bc7d6a5bab6178@linux-foundation.org> In-Reply-To: <20260823044118.1097121-2-xialonglong2025@163.com> References: <20260823044118.1097121-1-xialonglong2025@163.com> <20260823044118.1097121-2-xialonglong2025@163.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 719FD180002 X-Stat-Signature: tn6gbmi5iseagkhkjw7dma5fmkbh8edo X-HE-Tag: 1787894575-327381 X-HE-Meta: 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 FmTioQ33 KOGazBJMsgHU5UykDgxWk6Fbr3cm11SFpZSZTpayLgSRSuS75P4o2McXuiSlGBCvHr2jri86hPpg93I/4rjCXkX2idEyXKDhLWNAtVrEWDqAlKZw0m0JxgZgczWlc2bjAT/IKAi1eoVVp7XlStusMmMdqOvLZLeUyIxeVNBTm5EVuU9yFkKoKPIInAV+GVq7Atul5jkRgXFC8cdPGh4opBCWfMN1lgg+Aa5oGIFexnzHhtaV1rGzDrerqPjBHD13e6ENsH7nxhHiM7nzhfpUO8Z2pU2SfsllgVZ8PMVoQh1EuGHozmF2QS87ADYg9/WJhcD0BAQ9MnPd3nRA= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, 23 Aug 2026 12:40:51 +0800 Longlong Xia wrote: > From: Longlong Xia > > dissolve_free_hugetlb_folio() doesn't check > hstate_is_gigantic_no_runtime(h) though remove_hugetlb_folio()/ > update_and_free_hugetlb_folio() silently bail for such folios, so it > frees a still-listed folio and, on vmemmap restore failure, the > add_hugetlb_folio() rollback corrupts the free list. > > Fixes: 6eb4e88a6d27 ("hugetlb: create remove_hugetlb_page() to separate functionality") > Assisted-by: Codex:gpt-5.6-sol > Signed-off-by: Longlong Xia This doesn't carry an explicit cc:stable, as you mentioned in the cover letter. And that's OK - people often omit it. Perhaps because the -stable people backport every dang thing which has a Fixes:. They've been asked not to do that for MM. Also, the changelogging doesn't provide reasons for backporting the fix. Please review Documentation/process/stable-kernel-rules.rst. The key thing is to include a description of the userspace-visible runtime effects of the bug. A reproducer, a Reported-by:, a Closes:, etc. *something* to explain to people why they should make this change to their kernel. >From the v1 review discussion it appears that this fix was inspired by a Sashiko report? Changelogging this detail would be helpful. I asked Gemini to create a reproducer for this (https://share.gemini.google/be2PvvOLw6kx) and it's very involved. Makes me suspect that nobody has hit this in real life? Muchun's ack wasn't carried over from the v1 patch? Thanks, I'll apply the patches (hoping for additional review) but at this stage I'm not really sure *why* I"m applying them! btw, there wasn't anything in the [0/N] cover letter which was usable in a cover letter. But that's OK - I'll split the series apart anyway Because [1/1] is cc:stable so it will take a different path into mainline, with different timing. hm, anyway, that was lengthy. Please send along a few additional words telling people why we feel this should be backported?