diff options
| author | Anthony Yznaga <anthony.yznaga@oracle.com> | 2026-03-10 18:58:20 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-04-05 23:53:25 +0300 |
| commit | d239462787b072c78eb19fc1f155c3d411256282 (patch) | |
| tree | 21bcab3a430c78ed4c0aed1b79fca57eef9b7b7a /tools/testing | |
| parent | 301f3922009658ee353b3177bc186a12d36b8dd3 (diff) | |
| download | linux-d239462787b072c78eb19fc1f155c3d411256282.tar.xz | |
mm: prevent droppable mappings from being locked
Droppable mappings must not be lockable. There is a check for VMAs with
VM_DROPPABLE set in mlock_fixup() along with checks for other types of
unlockable VMAs which ensures this when calling mlock()/mlock2().
For mlockall(MCL_FUTURE), the check for unlockable VMAs is different. In
apply_mlockall_flags(), if the flags parameter has MCL_FUTURE set, the
current task's mm's default VMA flag field mm->def_flags has VM_LOCKED
applied to it. VM_LOCKONFAULT is also applied if MCL_ONFAULT is also set.
When these flags are set as default in this manner they are cleared in
__mmap_complete() for new mappings that do not support mlock. A check for
VM_DROPPABLE in __mmap_complete() is missing resulting in droppable
mappings created with VM_LOCKED set. To fix this and reduce that chance
of similar bugs in the future, introduce and use vma_supports_mlock().
Link: https://lkml.kernel.org/r/20260310155821.17869-1-anthony.yznaga@oracle.com
Fixes: 9651fcedf7b9 ("mm: add MAP_DROPPABLE for designating always lazily freeable mappings")
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Suggested-by: David Hildenbrand <david@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Reviewed-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Tested-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Jason A. Donenfeld <jason@zx2c4.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'tools/testing')
| -rw-r--r-- | tools/testing/vma/include/stubs.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/tools/testing/vma/include/stubs.h b/tools/testing/vma/include/stubs.h index 947a3a0c2566..416bb93f5005 100644 --- a/tools/testing/vma/include/stubs.h +++ b/tools/testing/vma/include/stubs.h @@ -426,3 +426,8 @@ static inline void vma_adjust_trans_huge(struct vm_area_struct *vma, } static inline void hugetlb_split(struct vm_area_struct *, unsigned long) {} + +static inline bool vma_supports_mlock(const struct vm_area_struct *vma) +{ + return false; +} |