kernel/linux.git/mm, branch v7.0.12

Revert "mm/hugetlbfs: update hugetlbfs to use mmap_prepare"

2026-06-09T10:32:49+00:00

commit 83f9efcce93f8574be2279090ee2aec58b86cda7 upstream. This reverts commit ea52cb24cd3f ("mm/hugetlbfs: update hugetlbfs to use mmap_prepare") with conflict resolution to account for changes in commit ea52cb24cd3f ("mm/hugetlbfs: update hugetlbfs to use mmap_prepare"). The patch incorrectly handled hugetlb VMA lock allocation at the mmap_prepare stage, where a failed allocation occurring after mmap_prepare is called might result in the lock leaking. There is no risk of a merge causing a similar issues, as VMA_DONTEXPAND_BIT is set for hugetlb mappings. As a first step in addressing this issue, simply revert the change so we can rework how we do this having corrected the underlying issues. We maintain the VMA flags changes as best we can, accounting for the fact that we were working with a VMA descriptor previously and propagating like-for-like changes for this. Note that we invoke vma_set_flags() and do not call vma_start_write() as vm_flags_set() does. This is OK as it's being done in an .mmap hook where the VMA is not yet linked into the tree so nobody else can be accessing it. Link: https://lore.kernel.org/20260512160643.266960-1-ljs@kernel.org Fixes: ea52cb24cd3f ("mm/hugetlbfs: update hugetlbfs to use mmap_prepare") Signed-off-by: Lorenzo Stoakes Reported-by: Mingyu Wang <25181214217@stu.xidian.edu.cn> Closes: https://lore.kernel.org/linux-mm/20260425070700.562229-1-25181214217@stu.xidian.edu.cn/ Acked-by: Muchun Song Acked-by: Oscar Salvador Cc: David Hildenbrand Cc: Liam R. Howlett Cc: Pedro Falcato Cc: Signed-off-by: Andrew Morton Signed-off-by: Lorenzo Stoakes Signed-off-by: Greg Kroah-Hartman

mm/rmap: initialize nr_pages to 1 at loop start in try_to_unmap_one

2026-06-09T10:32:32+00:00

commit 3f8968e9cbf95d5d87d32218906cab0b9b9eddbe upstream. Initialize nr_pages to 1 at the start of each loop iteration, like folio_referenced_one() does. Without this, nr_pages computed by a previous folio_unmap_pte_batch() call can be reused on a later iteration that does not run folio_unmap_pte_batch() again. mmap a 64K large folio with MAP_ANONYMOUS | MAP_DROPPABLE, then call madvise(MADV_FREE), then make the last page device-exclusive via HMM_DMIRROR_EXCLUSIVE. Trigger node reclaim through sysfs. Now, in try_to_unmap_one(), we will first clear the first 15 out of 16 entries mapping the lazyfree folio. This will set nr_pages to 15. In the next pvmw walk, this nr_pages gets reused on a device-exclusive pte, thus potentially corrupting folio refcount/mapcount. At the moment, I have a userspace program which can make the kernel spit out a trace, but the blow up is in folio_referenced_one(), because there are existing bugs in the interaction between device-private and rmap (which too I am investigating). I did a one liner kernel change to avoid going into folio_referenced_one(), and the kernel blows up at folio_remove_rmap_ptes in try_to_unmap_one which is what I wanted. Note that the bug is there not since file folio batching but lazyfree folio batching, since device-exclusive only works for anonymous folios. Userspace visible effect is simply kernel crashing somewhere due to refcount/mapcount corruption. Link: https://lore.kernel.org/20260518063656.3721056-1-dev.jain@arm.com Fixes: 354dffd29575 ("mm: support batched unmap for lazyfree large folios during reclamation") Signed-off-by: Dev Jain Acked-by: Barry Song Acked-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes Cc: Anshuman Khandual Cc: Barry Song Cc: Dev Jain Cc: Harry Yoo Cc: Jann Horn Cc: Liam R. Howlett Cc: Rik van Riel Cc: Ryan Roberts Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

memfd: deny writeable mappings when implying SEAL_WRITE

2026-06-09T10:32:31+00:00

commit 3b041514cb6eae45869b020f743c14d983363222 upstream. When SEAL_EXEC is added, SEAL_WRITE is implied to make W^X. But the implied seal is set after the check that makes sure the memfd can not have any writable mappings. This means one can use SEAL_EXEC to apply SEAL_WRITE while having writeable mappings. This breaks the contract that SEAL_WRITE provides and can be used by an attacker to pass a memfd that appears to be write sealed but can still be modified arbitrarily. Fix this by adding the implied seals before the call for mapping_deny_writable() is done. Link: https://lore.kernel.org/20260505133922.797635-1-pratyush@kernel.org Fixes: c4f75bc8bd6b ("mm/memfd: add write seals when apply SEAL_EXEC to executable memfd") Signed-off-by: Pratyush Yadav (Google) Reviewed-by: Pasha Tatashin Acked-by: Jeff Xu Cc: Baolin Wang Cc: Brendan Jackman Cc: Greg Thelen Cc: Hugh Dickins Cc: Kees Cook Cc: "David Hildenbrand (Arm)" Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/migrate_device: fix pgtable leak in migrate_vma_insert_huge_pmd_page

2026-06-09T10:32:31+00:00

commit 2c6f81d58741349298f51ff697d988cb42881453 upstream. When migrate_vma_insert_huge_pmd_page() jumps to unlock_abort due to a PMD check failure, the pgtable allocated earlier via pte_alloc_one() is never freed, causing a memory leak. Added free_abort label to release the pgtable in error path. Link: https://lore.kernel.org/20260501115122.23288-1-nueralspacetech@gmail.com Fixes: a30b48bf1b24 ("mm/migrate_device: implement THP migration of zone device pages") Signed-off-by: Sunny Patel Acked-by: David Hildenbrand (Arm) Reviewed-by: Huang Ying Cc: Alistair Popple Cc: Balbir Singh Cc: Byungchul Park Cc: Gregory Price Cc: Joshua Hahn Cc: Matthew Brost Cc: Rakie Kim Cc: Zi Yan Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm: memcontrol: propagate NMI slab stats to memcg vmstats

2026-06-09T10:32:31+00:00

commit e16f17a9c5af50221184d1ef4be4056bf3c4209e upstream. flush_nmi_stats() drains per-node NMI slab atomics into the per-node lruvec_stats, but does not propagate them to the memcg-level vmstats. For non NMI case, account_slab_nmi_safe() calls mod_memcg_lruvec_state() which updates both per-node lruvec_stats and memcg-level vmstats, so flush_nmi_stats() needs to flush to per-node lruvec_stats as well as memcg-level vmstats. So fix this by flushing to the memcg-level vmstats for NMI too. Link: https://lore.kernel.org/20260518082830.599102-1-alex@ghiti.fr Fixes: 940b01fc8dc1 ("memcg: nmi safe memcg stats for specific archs") Signed-off-by: Alexandre Ghiti Acked-by: Shakeel Butt Acked-by: Johannes Weiner Reviewed-by: Harry Yoo (Oracle) Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()

2026-06-09T10:32:31+00:00

commit 441f92f7d386b85bad16de49db95a307cba048a2 upstream. DAMON sysfs maintains the DAMOS tried region directory objects via a linked list. When the user requests refresh of the directories, DAMON sysfs removes all the region directories first, and then generate updated regions directory on the empty space. The removal function (damon_sysfs_scheme_regions_rm_dirs()) only puts the kobj objects. Deletion of the container region object from the linked list is done inside the kobj release callback function. If somehow the callback invocation is delayed, the list will contain regions list that gonna be freed. If the updated region directories creation is started in this situation, the list can be corrupted and use-after-free can happen. Because the kobj objects are managed by only DAMON sysfs, the issue cannot happen in normal situation. But, such delays can be made on kernels that built with CONFIG_DEBUG_KOBJECT_RELEASE. On the kernel, the issue can indeed be reproduced like below. # damo start --damos_action stat # cd /sys/kernel/mm/damon/admin/kdamonds/0/ # for i in {1..10}; do echo update_schemes_tried_regions > state; done # dmesg | grep underflow [ 89.296152] refcount_t: underflow; use-after-free. Fix the issue by removing the region object from the list when decrementing the reference count. Also update damos_sysfs_populate_region_dir() to add the region object to the list only after the kobject_init_and_add() is success, so that fail of kobject_init_and_add() is not leaving the deallocated object on the list. The issue was discovered [1] by Sashiko. Link: https://lore.kernel.org/20260518152559.93038-1-sj@kernel.org Link: https://lore.kernel.org/20260513011920.119183-1-sj@kernel.org [1] Fixes: 9277d0367ba1 ("mm/damon/sysfs-schemes: implement scheme region directory") Signed-off-by: SeongJae Park Cc: # 6.2.x Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/vmalloc: do not trigger BUG() on BH disabled context

2026-06-09T10:32:31+00:00

commit 04aa71da5f35aacdc9ae9cb5150947daa624f641 upstream. __get_vm_area_node() currently triggers a BUG() if in_interrupt() returns true. However, in_interrupt() also reports true when BH are disabled. The bridge code can call rhashtable_lookup_insert_fast() with bottom halves disabled: __vlan_add() -> br_fdb_add_local() spin_lock_bh(&br->hash_lock); <-- Disable BH -> fdb_add_local() -> fdb_create() -> rhashtable_lookup_insert_fast() -> kvmalloc() -> vmalloc() -> __get_vm_area_node() -> BUG_ON(in_interrupt()) spin_unlock_bh(&br->hash_lock) this triggers the BUG() despite the caller not being in NMI or hard IRQ context. Replace the in_interrupt() check with in_nmi() || in_hardirq(). Link: https://lore.kernel.org/20260515153009.2296191-1-urezki@gmail.com Fixes: c6307674ed82 ("mm: kvmalloc: add non-blocking support for vmalloc") Signed-off-by: Uladzislau Rezki (Sony) Cc: Ido Schimmel Reported-by: syzbot+8b12fc6e0fb139765b58@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69ff8c7c.050a0220.1036b8.000b.GAE@google.com/ Reviewed-by: Baoquan He Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

cgroup/rstat: validate cpu before css_rstat_cpu() access

2026-06-01T15:54:48+00:00

[ Upstream commit 8817005efbdfdf5d4e4814cb5dc52b53d12917d7 ] css_rstat_updated() is exposed as a BPF kfunc and accepts a caller-provided cpu argument. The function uses cpu for per-cpu rstat lookups without checking whether it refers to a valid possible CPU. A BPF iter/cgroup program with CAP_BPF and CAP_PERFMON can pass an invalid cpu value. On an unfixed UBSCAN_BOUNDS test kernel, cpu == 0x7fffffff triggers: UBSAN: array-index-out-of-bounds in kernel/cgroup/rstat.c:31:9 index 2147483647 is out of range for type 'long unsigned int [64]' Call Trace: css_rstat_updated bpf_iter_run_prog cgroup_iter_seq_show bpf_seq_read Add cpu validation to the BPF-facing css_rstat_updated() kfunc and move the common implementation to __css_rstat_updated() for in-kernel callers. Fixes: a319185be9f5 ("cgroup: bpf: enable bpf programs to integrate with rstat") Signed-off-by: Qing Ming Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin

mm/memfd_luo: report error when restoring a folio fails mid-loop

2026-06-01T15:54:33+00:00

[ Upstream commit 0fb1daf0b78d0e23b63b6b65de56d4a3fd83bc14 ] memfd_luo_retrieve_folios() initialises err to -EIO, but the per-iteration calls to mem_cgroup_charge(), shmem_add_to_page_cache() and shmem_inode_acct_blocks() reuse and overwrite err. Once any iteration completes successfully, err becomes zero. If a later iteration's kho_restore_folio() returns NULL, the failure path jumps to put_folios without resetting err, so the function returns 0. The caller memfd_luo_retrieve() then takes the success path, sets args->file and reports the restore as successful, leaving userspace with a partially populated memfd and no indication that anything went wrong. Set err to -EIO in the kho_restore_folio() failure branch so the error is propagated to the caller. Signed-off-by: David Carlier Reviewed-by: Pratyush Yadav Fixes: b3749f174d68 ("mm: memfd_luo: allow preserving memfd") Link: https://patch.msgid.link/20260415052300.362539-1-devnexen@gmail.com Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Sasha Levin

mm/slub: hold cpus_read_lock around flush_rcu_sheaves_on_cache()

2026-06-01T15:54:28+00:00

commit 67ea9d353d0ba12bdbc9183ff568dead9e949b80 upstream. flush_rcu_sheaves_on_cache() calls queue_work_on() in a for_each_online_cpu() loop, which requires the cpu to stay online. But cpus_read_lock() is not held in kvfree_rcu_barrier_on_cache() and the set of "online cpus" is subject to change. There are two paths that call flush_rcu_sheaves_on_cache(): // has cpus_read_lock() flush_all_rcu_sheaves() -> flush_rcu_sheaves_on_cache() // no cpus_read_lock() kvfree_rcu_barrier_on_cache() -> flush_rcu_sheaves_on_cache() Fix this by holding cpus_read_lock() in kvfree_rcu_barrier_on_cache(). Why not move cpus_read_lock() from flush_all_rcu_sheaves() into flush_rcu_sheaves_on_cache()? The reason is it would introduce a new lock order (slab_mutex -> cpu_hotplug_lock). The reverse order (cpu_hotplug_lock -> slab_mutex) is established by - cpuhp_setup_state_nocalls(..., slub_cpu_setup, ...) - kmem_cache_destroy() The two orders together would form an AB-BA deadlock. Finally, add lockdep_assert_cpus_held() in flush_rcu_sheaves_on_cache() to catch the same problem in the future. Fixes: 0f35040de593 ("mm/slab: introduce kvfree_rcu_barrier_on_cache() for cache destruction") Cc: Signed-off-by: Qing Wang Link: https://patch.msgid.link/20260512035035.762317-1-wangqing7171@gmail.com Signed-off-by: Vlastimil Babka (SUSE) Signed-off-by: Greg Kroah-Hartman