The patch titled
Subject: fs/userfaultfd: fix maple state in userfaultfd_register()
has been added to the -mm tree. Its filename is
userfaultfd-use-maple-tree-iterator-to-iterate-vmas-fix.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-use-maple-tree-iterator-to-iterate-vmas-fix.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-use-maple-tree-iterator-to-iterate-vmas-fix.patch
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The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Liam Howlett <liam.howlett@xxxxxxxxxx>
Subject: fs/userfaultfd: fix maple state in userfaultfd_register()
When VMAs are split/merged, the maple tree node may be replaced. Re-walk
the tree in such cases by calling mas_pause().
Link: https://lkml.kernel.org/r/20220427154314.2o32gn46323hllnb@revolver
Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/userfaultfd.c | 6 ++++++
1 file changed, 6 insertions(+)
--- a/fs/userfaultfd.c~userfaultfd-use-maple-tree-iterator-to-iterate-vmas-fix
+++ a/fs/userfaultfd.c
@@ -1437,6 +1437,8 @@ static int userfaultfd_register(struct u
((struct vm_userfaultfd_ctx){ ctx }),
anon_vma_name(vma));
if (prev) {
+ /* vma_merge() invalidated the mas */
+ mas_pause(&mas);
vma = prev;
goto next;
}
@@ -1444,11 +1446,15 @@ static int userfaultfd_register(struct u
ret = split_vma(mm, vma, start, 1);
if (ret)
break;
+ /* split_vma() invalidated the mas */
+ mas_pause(&mas);
}
if (vma->vm_end > end) {
ret = split_vma(mm, vma, end, 0);
if (ret)
break;
+ /* split_vma() invalidated the mas */
+ mas_pause(&mas);
}
next:
/*
_
Patches currently in -mm which might be from liam.howlett@xxxxxxxxxx are
maple-tree-add-new-data-structure-fix.patch
userfaultfd-use-maple-tree-iterator-to-iterate-vmas-fix.patch
