From: Rik van Riel <riel@surriel.com>
To: "David Hildenbrand (Arm)" <david@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>, Qi Zheng <qi.zheng@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Lorenzo Stoakes <ljs@kernel.org>,
Kairui Song <kasong@tencent.com>, Barry Song <baohua@kernel.org>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
Baoquan He <baoquan.he@linux.dev>,
Baolin Wang <baolin.wang@linux.alibaba.com>,
"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>, Kees Cook <kees@kernel.org>,
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Hugh Dickins <hughd@google.com>,
Pasha Tatashin <pasha.tatashin@soleen.com>,
Pratyush Yadav <pratyush@kernel.org>,
"Matthew Wilcox (Oracle)" <willy@infradead.org>,
Jan Kara <jack@suse.cz>, Zi Yan <ziy@nvidia.com>,
Lance Yang <lance.yang@linux.dev>, Harry Yoo <harry@kernel.org>,
Alistair Popple <apopple@nvidia.com>,
Nico Pache <nico.pache@linux.dev>,
Ryan Roberts <ryan.roberts@arm.com>, Dev Jain <dev.jain@arm.com>,
Usama Arif <usama.arif@linux.dev>,
Kiryl Shutsemau <kas@kernel.org>,
Matthew Brost <matthew.brost@intel.com>,
John Hubbard <jhubbard@nvidia.com>, Peter Xu <peterx@redhat.com>,
Will Deacon <will@kernel.org>,
"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
Nick Piggin <npiggin@gmail.com>,
Oscar Salvador <osalvador@suse.de>,
Minchan Kim <minchan@kernel.org>,
Muchun Song <muchun.song@linux.dev>, Xu Xin <xu.xin@linux.dev>,
Chengming Zhou <chengming.zhou@linux.dev>,
Chris Li <chrisl@kernel.org>,
Kemeng Shi <shikemeng@huaweicloud.com>,
Nhat Pham <nphamcs@gmail.com>,
Youngjun Park <youngjun.park@lge.com>,
Gregory Price <gourry@gourry.net>,
Joshua Hahn <joshua.hahnjy@gmail.com>,
Rakie Kim <rakie.kim@sk.com>,
Ying Huang <ying.huang@linux.alibaba.com>,
Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org,
linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org,
Josef Bacik <josef@toxicpanda.com>,
stable@vger.kernel.org
Subject: Re: [PATCH 04/46] mm/memfd: make f_pos accesses atomic
Date: Mon, 26 Oct 2026 22:06:47 -0400 [thread overview]
Message-ID: <639cb6dca4ab423272e05b90562ec49c7bdb12f9.camel@surriel.com> (raw)
In-Reply-To: <20261027-fixes_core-v1-4-6f74bec9a5bb@kernel.org>
On Tue, 2026-10-27 at 00:17 +0100, David Hildenbrand (Arm) wrote:
> From: Josef Bacik <josef@toxicpanda.com>
>
>
> Set the flag when the memfd is created. As for any other regular
> file the
> lock is only taken if the file is reachable in more than one way, and
> nothing a memfd does in read or write waits for another operation on
> the
> same file. This cannot be done for all alloc_file_pseudo() files:
> anon
> inode files such as eventfd are S_IFREG as well, and a blocked read
> holding
> ->f_pos_lock would lock out the write that is supposed to wake it.
>
> Fix generated by an LLM and sent by Josef Bacik in private.
>
> Fixes: 9183df25fe7b ("shm: add memfd_create() syscall")
> Cc: stable@vger.kernel.org
> Signed-off-by: Josef Bacik <josef@toxicpanda.com>
> [ david: minor description tweaks ]
> Signed-off-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Rik van Riel <riel@surriel.com>
--
All Rights Reversed.
next prev parent reply other threads:[~2026-10-27 2:08 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-26 23:17 [PATCH 00/46] mm: various (urgent?) fixes David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 01/46] mm/mglru: don't use stack pointers when walking PUD and PMD tables David Hildenbrand (Arm)
2026-10-27 1:32 ` Rik van Riel
2026-10-27 3:05 ` Qi Zheng
2026-10-27 7:20 ` Dev Jain
2026-10-26 23:17 ` [PATCH 02/46] fork: take mmap_lock before copying mm_struct David Hildenbrand (Arm)
2026-10-27 1:38 ` Rik van Riel
2026-10-26 23:17 ` [PATCH 03/46] mm/memfd: check for real shmem inodes before accessing shmem state David Hildenbrand (Arm)
2026-10-27 2:04 ` Rik van Riel
2026-10-26 23:17 ` [PATCH 04/46] mm/memfd: make f_pos accesses atomic David Hildenbrand (Arm)
2026-10-27 2:06 ` Rik van Riel [this message]
2026-10-27 3:34 ` Gregory Price
2026-10-26 23:17 ` [PATCH 05/46] mm/truncate: look again if a folio left the mapping David Hildenbrand (Arm)
2026-10-27 2:17 ` Rik van Riel
2026-10-26 23:17 ` [PATCH 06/46] mm/filemap: read mapping->a_ops->free_folio under i_lock David Hildenbrand (Arm)
2026-10-27 2:43 ` Rik van Riel
2026-10-26 23:17 ` [PATCH 07/46] mm/filemap: don't lose a folio lock wakeup to a signal David Hildenbrand (Arm)
2026-10-27 3:03 ` Rik van Riel
2026-10-26 23:17 ` [PATCH 08/46] mm/filemap: finish fault cleanup before dropping the fault lock David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 09/46] mm/rmap: handle device-exclusive entries in folio_referenced_one() David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 10/46] mm/huge_memory: fix list corruption when deferred_split_scan() races with deferred_split_folio() David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 11/46] mm/huge_memory: properly handle refcounted PUD mappings on fork David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 12/46] mm/huge_memory: fix livelock on device private folio David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 13/46] mm/huge_memory: fix truncate racing with PMD zapping David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 14/46] mm/huge_memory: fix zapping migration entries for device-private THPs David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 15/46] mm/khugepaged: always recheck the pmd in try_collapse_pte_mapped_thp() David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 16/46] mm/khugepaged: fix PMD table lock leak " David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 17/46] mm/khugepaged: preserve dirty bits when collapsing PTE-mapped THPs David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 18/46] mm/khugepaged: check if PTE table is empty in try_collapse_pte_mapped_thp() David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 19/46] mm/gup: recheck the PUD under PTL in follow_pud_mask() David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 20/46] mm/gup: fix clearing folios in memfd_pin_folios() David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 21/46] mm/gup: fix out-of-bounds write for nr_pages == 0 in GUP-fast David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 22/46] mm/gup: check for overflow when converting nr_pages to bytes " David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 23/46] mm/userfaultfd: write-lock the VMA before waking waiters when unregistering David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 24/46] mm/userfaultfd: wake all waiters on unregister David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 25/46] mm/userfaultfd: wake waiters when registration modes are removed David Hildenbrand (Arm)
2026-10-27 5:10 ` Gregory Price
2026-10-26 23:17 ` [PATCH 26/46] mm/mmu_gather: fix flushing ranges with 4 GiB or larger David Hildenbrand (Arm)
2026-10-27 3:06 ` Qi Zheng
2026-10-27 3:40 ` Gregory Price
2026-10-26 23:17 ` [PATCH 27/46] mm/mmu_notifier: finish non-blocking interval invalidation on error David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 28/46] mm/mmu_notifier: set ->mm only after mmgrab() David Hildenbrand (Arm)
2026-10-27 3:42 ` Gregory Price
2026-10-26 23:17 ` [PATCH 29/46] mm/mremap: use pudp_huge_get_and_clear() when moving huge PUDs David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 30/46] mm/mremap: recheck PUDs under the page table lock David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 31/46] mm/mremap: fix moving PUD leaves David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 32/46] mm/memory_hotplug: avoid races in pfn_to_online_page() with dying pgmap David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 33/46] mm/madvise: fix data loss from MADV_FREE on a KSM page David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 34/46] mm/memory: reject remote COW faults on PFN mappings David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 35/46] mm: fix unmap_mapping_range() beyond 4 GiB on 32-bit David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 36/46] mm: fix unkillable fault loop on MAP_DROPPABLE memory David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 37/46] mm: fix deadlock of mremap() against UFFDIO_MOVE David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 38/46] mm/ksm: reset the unstable trees of all nodes David Hildenbrand (Arm)
2026-10-26 23:17 ` [PATCH 39/46] mm/ksm: fix use of a freed anon_vma at swap-in David Hildenbrand (Arm)
2026-10-26 23:18 ` [PATCH 40/46] mm/ksm: check large swap-cache folios before mapping them David Hildenbrand (Arm)
2026-10-26 23:18 ` [PATCH 41/46] mm/vma: call ->may_split() before a partial merge David Hildenbrand (Arm)
2026-10-27 3:45 ` Gregory Price
2026-10-26 23:18 ` [PATCH 42/46] mm/huge_memory: split huge PUDs when adjusting VMA boundaries David Hildenbrand (Arm)
2026-10-26 23:18 ` [PATCH 43/46] mm/vma: don't leak the charge for stack growth David Hildenbrand (Arm)
2026-10-26 23:18 ` [PATCH 44/46] mm/cma: don't release CMA pages still in use David Hildenbrand (Arm)
2026-10-26 23:18 ` [PATCH 45/46] mm/memory-tiers: unregister empty tiers outside memory_tier_lock David Hildenbrand (Arm)
2026-10-26 23:18 ` [PATCH 46/46] fs/proc/task_mmu: refuse addresses beyond 32 bits on 32bit David Hildenbrand (Arm)
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