The patch titled
Subject: mm/mlock: set the correct prev on failure
has been added to the -mm mm-unstable branch. Its filename is
mm-mlock-set-the-correct-prev-on-failure.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mlock-set-the-correct-prev-on-failure.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Wei Yang <richard.weiyang@xxxxxxxxx>
Subject: mm/mlock: set the correct prev on failure
Date: Sun, 27 Oct 2024 12:33:21 +0000
After commit 94d7d9233951 ("mm: abstract the vma_merge()/split_vma()
pattern for mprotect() et al."), if vma_modify_flags() return error, the
vma is set to an error code. This will lead to an invalid prev be
returned.
Generally this shouldn't matter as the caller should treat an error as
indicating state is now invalidated, however unfortunately
apply_mlockall_flags() does not check for errors and assumes that
mlock_fixup() correctly maintains prev even if an error were to occur.
This patch fixes that assumption.
[lorenzo.stoakes@xxxxxxxxxx: provide a better fix and rephrase the log]
Link: https://lkml.kernel.org/r/20241027123321.19511-1-richard.weiyang@xxxxxxxxx
Fixes: 94d7d9233951 ("mm: abstract the vma_merge()/split_vma() pattern for mprotect() et al.")
Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mlock.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/mm/mlock.c~mm-mlock-set-the-correct-prev-on-failure
+++ a/mm/mlock.c
@@ -725,14 +725,17 @@ static int apply_mlockall_flags(int flag
}
for_each_vma(vmi, vma) {
+ int error;
vm_flags_t newflags;
newflags = vma->vm_flags & ~VM_LOCKED_MASK;
newflags |= to_add;
- /* Ignore errors */
- mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end,
- newflags);
+ error = mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end,
+ newflags);
+ /* Ignore errors, but prev needs fixing up. */
+ if (error)
+ prev = vma;
cond_resched();
}
out:
_
Patches currently in -mm which might be from richard.weiyang@xxxxxxxxx are
maple_tree-i-is-always-less-than-or-equal-to-mas_end.patch
maple_tree-goto-complete-directly-on-a-pivot-of-0.patch
maple_tree-remove-maple_big_nodeparent.patch
maple_tree-memset-maple_big_node-as-a-whole.patch
maple_tree-root-node-could-be-handled-by-p_slot-too.patch
maple_tree-clear-request_count-for-new-allocated-one.patch
maple_tree-total-is-not-changed-for-nomem_one-case.patch
maple_tree-simplify-mas_push_node.patch
maple_tree-calculate-new_end-when-needed.patch
maple_tree-remove-sanity-check-from-mas_wr_slot_store.patch
mm-vma-the-pgoff-is-correct-if-can_merge_right.patch
mm-mlock-set-the-correct-prev-on-failure.patch
