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From: "Jose A. Perez de Azpillaga" <azpijr@gmail.com>
To: "David Hildenbrand (Arm)" <david@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Lorenzo Stoakes <ljs@kernel.org>,
	"Liam R. Howlett" <liam@infradead.org>,
	Vlastimil Babka <vbabka@kernel.org>,
	Mike Rapoport <rppt@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Michal Hocko <mhocko@suse.com>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Jan Kara <jack@suse.cz>, Zi Yan <ziy@nvidia.com>,
	Baolin Wang <baolin.wang@linux.alibaba.com>,
	Nico Pache <nico.pache@linux.dev>,
	Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
	Barry Song <baohua@kernel.org>, Lance Yang <lance.yang@linux.dev>,
	Usama Arif <usama.arif@linux.dev>,
	Kiryl Shutsemau <kas@kernel.org>,
	Matthew Brost <matthew.brost@intel.com>,
	Joshua Hahn <joshua.hahnjy@gmail.com>,
	Byungchul Park <byungchul@sk.com>,
	Gregory Price <gourry@gourry.net>,
	Ying Huang <ying.huang@linux.alibaba.com>,
	Alistair Popple <apopple@nvidia.com>,
	Peter Xu <peterx@redhat.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Song Liu <songliubraving@fb.com>, Rik van Riel <riel@surriel.com>,
	Hugh Dickins <hughd@google.com>, Will Deacon <will@kernel.org>,
	"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
	Nick Piggin <npiggin@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Jason Gunthorpe <jgg@ziepe.ca>, Kevin Tian <kevin.tian@intel.com>,
	"Joerg Roedel (AMD)" <joro@8bytes.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Steve Sistare <steven.sistare@oracle.com>,
	John Hubbard <jhubbard@nvidia.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org,
	iommu@lists.linux.dev, stable@vger.kernel.org
Subject: Re: [PATCH 2/5] mm: limit pagecache folio refcount when splicing into pipes
Date: Fri, 6 Nov 2026 10:50:34 +0100	[thread overview]
Message-ID: <6662ae76-c8dc-4bc5-9730-bf9f537ca9cb@gmail.com> (raw)
In-Reply-To: <20261105-refcount_overflow_stable-v1-2-70b9c655da3e@kernel.org>

On 11/5/26 2:10 PM, David Hildenbrand (Arm) wrote:
> Similar to mapping pagecache folios into page tables, let's reject splicing
> folios into a pipe if the refcount is at it's limit, similar to how we
> handle it during GUP.
> 
> This will prevent more cases of possible folio refcount overflows with
> large pagecache folios.
> 
> Let's keep it simple and check in the two callers of
> splice_folio_into_pipe().
> 
> Also check in try_get_page() to cover pipe-buffer duplication by tee()
> and partial pipe-to-pipe splicing.
> 
> Fixes: 800d8c63b2e9 ("shmem: add huge pages support")
> Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
> Fixes: 793917d997df ("mm/readahead: Add large folio readahead")
> Cc: stable@vger.kernel.org
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>

LGTM:

Reviewed-by: Jose A. Perez de Azpillaga <azpijr@gmail.com>

-- 
cheers,
jose a. p-a

  reply	other threads:[~2026-11-06  9:50 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-11-05 13:10 [PATCH 0/5] mm: limit pagecache folio refcount David Hildenbrand (Arm)
2026-11-05 13:10 ` [PATCH 1/5] mm: limit pagecache folio refcount when mapping pages David Hildenbrand (Arm)
2026-11-06  9:11   ` Lance Yang
2026-11-06  9:42   ` Jose A. Perez de Azpillaga
2026-11-06 10:05     ` David Hildenbrand (Arm)
2026-11-06 10:06     ` Lance Yang
2026-11-06 12:38   ` Kiryl Shutsemau
2026-11-05 13:10 ` [PATCH 2/5] mm: limit pagecache folio refcount when splicing into pipes David Hildenbrand (Arm)
2026-11-06  9:50   ` Jose A. Perez de Azpillaga [this message]
2026-11-06 10:03   ` Lance Yang
2026-11-06 17:58   ` Josef Bacik
2026-11-06 20:09     ` David Hildenbrand (Arm)
2026-11-06 20:43       ` Jason Gunthorpe
2026-11-06 20:45         ` David Hildenbrand (Arm)
2026-11-05 13:10 ` [PATCH 3/5] mm/mmu_gather: flush pending references early before the folio limit David Hildenbrand (Arm)
2026-11-06  9:56   ` Jose A. Perez de Azpillaga
2026-11-06 15:15   ` Lance Yang
2026-11-05 13:10 ` [PATCH 4/5] iommufd: fix cleanup when adding memfd folio pins fails David Hildenbrand (Arm)
2026-11-06 15:39   ` Lance Yang
2026-11-06 20:46   ` Jason Gunthorpe
2026-11-05 13:10 ` [PATCH 5/5] mm/gup: limit pagecache folio refcount when grabbing references David Hildenbrand (Arm)
2026-11-06 10:13   ` Jose A. Perez de Azpillaga
2026-11-05 17:51 ` [PATCH 0/5] mm: limit pagecache folio refcount David Hildenbrand (Arm)
2026-11-06 19:49 ` Josef Bacik
2026-11-06 20:31   ` David Hildenbrand (Arm)

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