Commit 8e72033f authored by Gerald Schaefer's avatar Gerald Schaefer Committed by Linus Torvalds

thp: make MADV_HUGEPAGE check for mm->def_flags

This adds a check to hugepage_madvise(), to refuse MADV_HUGEPAGE if
VM_NOHUGEPAGE is set in mm->def_flags.  On s390, the VM_NOHUGEPAGE flag
will be set in mm->def_flags for kvm processes, to prevent any future thp
mappings.  In order to also prevent MADV_HUGEPAGE on such an mm,
hugepage_madvise() should check mm->def_flags.
Signed-off-by: default avatarGerald Schaefer <>
Cc: Andrea Arcangeli <>
Cc: Andi Kleen <>
Cc: Hugh Dickins <>
Cc: Hillf Danton <>
Cc: Martin Schwidefsky <>
Cc: Heiko Carstens <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 46dcde73
......@@ -1450,6 +1450,8 @@ out:
int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
struct mm_struct *mm = vma->vm_mm;
switch (advice) {
......@@ -1457,6 +1459,8 @@ int hugepage_madvise(struct vm_area_struct *vma,
if (*vm_flags & (VM_HUGEPAGE | VM_NO_THP))
return -EINVAL;
if (mm->def_flags & VM_NOHUGEPAGE)
return -EINVAL;
*vm_flags &= ~VM_NOHUGEPAGE;
*vm_flags |= VM_HUGEPAGE;
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