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charset="utf-8" Mappings created with MAP_DROPPABLE cannot be locked via mlock() due to the check in mlock_fixup(). However, they will be locked indirectly if they are created after mlockall(MCL_FUTURE). Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily f= reeable mappings") Signed-off-by: Anthony Yznaga --- include/linux/mm.h | 3 +++ mm/mlock.c | 4 ++-- mm/vma.c | 2 +- 3 files changed, 6 insertions(+), 3 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5be3d8a8f806..bb830574d112 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -574,6 +574,9 @@ enum { /* This mask represents all the VMA flag bits used by mlock */ #define VM_LOCKED_MASK (VM_LOCKED | VM_LOCKONFAULT) =20 +/* This mask prevents VMAs from being mlock'd */ +#define VM_NO_MLOCK_MASK (VM_SPECIAL | VM_DROPPABLE) + /* These flags can be updated atomically via VMA/mmap read lock. */ #define VM_ATOMIC_SET_ALLOWED VM_MAYBE_GUARD =20 diff --git a/mm/mlock.c b/mm/mlock.c index 2f699c3497a5..fd35c1e88c4c 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -472,9 +472,9 @@ static int mlock_fixup(struct vma_iterator *vmi, struct= vm_area_struct *vma, int ret =3D 0; vm_flags_t oldflags =3D vma->vm_flags; =20 - if (newflags =3D=3D oldflags || (oldflags & VM_SPECIAL) || + if (newflags =3D=3D oldflags || (oldflags & VM_NO_MLOCK_MASK) || is_vm_hugetlb_page(vma) || vma =3D=3D get_gate_vma(current->mm) || - vma_is_dax(vma) || vma_is_secretmem(vma) || (oldflags & VM_DROPPABLE)) + vma_is_dax(vma) || vma_is_secretmem(vma)) /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */ goto out; =20 diff --git a/mm/vma.c b/mm/vma.c index be64f781a3aa..1334622e4a03 100644 --- a/mm/vma.c +++ b/mm/vma.c @@ -2589,7 +2589,7 @@ static void __mmap_complete(struct mmap_state *map, s= truct vm_area_struct *vma) =20 vm_stat_account(mm, vma->vm_flags, map->pglen); if (vm_flags & VM_LOCKED) { - if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || + if ((vm_flags & VM_NO_MLOCK_MASK) || vma_is_dax(vma) || is_vm_hugetlb_page(vma) || vma =3D=3D get_gate_vma(mm)) vm_flags_clear(vma, VM_LOCKED_MASK); --=20 2.47.3