mremap() is modifying the VMA layout and thus must be protected against
the speculative page fault handler.
Signed-off-by: Laurent Dufour <ldufour@xxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/mm/mremap.c b/mm/mremap.c
index cd8a1b199ef9..9c7f69c9e80f 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -300,6 +300,10 @@ static unsigned long move_vma(struct vm_area_struct *vma,
if (!new_vma)
return -ENOMEM;
+ write_seqcount_begin(&vma->vm_sequence);
+ write_seqcount_begin_nested(&new_vma->vm_sequence,
+ SINGLE_DEPTH_NESTING);
+
moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len,
need_rmap_locks);
if (moved_len < old_len) {
@@ -316,6 +320,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
*/
move_page_tables(new_vma, new_addr, vma, old_addr, moved_len,
true);
+ write_seqcount_end(&vma->vm_sequence);
vma = new_vma;
old_len = new_len;
old_addr = new_addr;
@@ -324,7 +329,9 @@ static unsigned long move_vma(struct vm_area_struct *vma,
mremap_userfaultfd_prep(new_vma, uf);
arch_remap(mm, old_addr, old_addr + old_len,
new_addr, new_addr + new_len);
+ write_seqcount_end(&vma->vm_sequence);
}
+ write_seqcount_end(&new_vma->vm_sequence);
/* Conceal VM_ACCOUNT so old reservation is not undone */
if (vm_flags & VM_ACCOUNT) {
--
2.7.4
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
