mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-05-14 21:38:46 +02:00
Anthony Yznaga
d239462787
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: 9651fcedf7 ("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>
39 lines
687 B
C
39 lines
687 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_HUGETLB_INLINE_H
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#define _LINUX_HUGETLB_INLINE_H
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#include <linux/mm.h>
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#ifdef CONFIG_HUGETLB_PAGE
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static inline bool is_vm_hugetlb_flags(vm_flags_t vm_flags)
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{
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return !!(vm_flags & VM_HUGETLB);
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}
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static inline bool is_vma_hugetlb_flags(const vma_flags_t *flags)
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{
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return vma_flags_test_any(flags, VMA_HUGETLB_BIT);
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}
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#else
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static inline bool is_vm_hugetlb_flags(vm_flags_t vm_flags)
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{
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return false;
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}
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static inline bool is_vma_hugetlb_flags(const vma_flags_t *flags)
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{
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return false;
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}
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#endif
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static inline bool is_vm_hugetlb_page(const struct vm_area_struct *vma)
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{
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return is_vm_hugetlb_flags(vma->vm_flags);
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}
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#endif
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