The patch titled
Subject: mm: fix potential anon_vma locking issue in mprotect()
has been removed from the -mm tree. Its filename was
mm-fix-potential-anon_vma-locking-issue-in-mprotect.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Michel Lespinasse <walken@xxxxxxxxxx>
Subject: mm: fix potential anon_vma locking issue in mprotect()
Fix an anon_vma locking issue in the following situation:
- vma has no anon_vma
- next has an anon_vma
- vma is being shrunk / next is being expanded, due to an mprotect call
We need to take next's anon_vma lock to avoid races with rmap users (such
as page migration) while next is being expanded.
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Acked-by: Hugh Dickins <hughd@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff -puN mm/mmap.c~mm-fix-potential-anon_vma-locking-issue-in-mprotect mm/mmap.c
--- a/mm/mmap.c~mm-fix-potential-anon_vma-locking-issue-in-mprotect
+++ a/mm/mmap.c
@@ -573,8 +573,12 @@ again: remove_next = 1 + (end > next->
*/
if (vma->anon_vma && (importer || start != vma->vm_start)) {
anon_vma = vma->anon_vma;
+ VM_BUG_ON(adjust_next && next->anon_vma &&
+ anon_vma != next->anon_vma);
+ } else if (adjust_next && next->anon_vma)
+ anon_vma = next->anon_vma;
+ if (anon_vma)
anon_vma_lock(anon_vma);
- }
if (root) {
flush_dcache_mmap_lock(mapping);
_
Patches currently in -mm which might be from walken@xxxxxxxxxx are
origin.patch
prio_tree-remove-fix.patch
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