The patch titled Subject: mm/mlock: fix vma iterator conversion of apply_vma_lock_flags() has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-mlock-fix-vma-iterator-conversion-of-apply_vma_lock_flags.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: "Liam R. Howlett" Liam.Howlett@oracle.com Subject: mm/mlock: fix vma iterator conversion of apply_vma_lock_flags() Date: Tue, 11 Jul 2023 13:50:20 -0400

apply_vma_lock_flags() calls mlock_fixup(), which could merge the VMA after where the vma iterator is located. Although this is not an issue, the next iteration of the loop will check the start of the vma to be equal to the locally saved 'tmp' variable and cause an incorrect failure scenario. Fix the error by setting tmp to the end of the vma iterator value before restarting the loop.

There is also a potential of the error code being overwritten when the loop terminates early. Fix the return issue by directly returning when an error is encountered since there is nothing to undo after the loop.

Link: https://lkml.kernel.org/r/20230711175020.4091336-1-Liam.Howlett@oracle.com Fixes: 37598f5a9d8b ("mlock: convert mlock to vma iterator") Signed-off-by: Liam R. Howlett Liam.Howlett@oracle.com Reported-by: Ryan Roberts ryan.roberts@arm.com Link: https://lore.kernel.org/linux-mm/50341ca1-d582-b33a-e3d0-acb08a65166f@arm.co... Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/mlock.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/mm/mlock.c~mm-mlock-fix-vma-iterator-conversion-of-apply_vma_lock_flags +++ a/mm/mlock.c @@ -477,7 +477,6 @@ static int apply_vma_lock_flags(unsigned { unsigned long nstart, end, tmp; struct vm_area_struct *vma, *prev; - int error; VMA_ITERATOR(vmi, current->mm, start);

VM_BUG_ON(offset_in_page(start)); @@ -498,6 +497,7 @@ static int apply_vma_lock_flags(unsigned nstart = start; tmp = vma->vm_start; for_each_vma_range(vmi, vma, end) { + int error; vm_flags_t newflags;

if (vma->vm_start != tmp) @@ -511,14 +511,15 @@ static int apply_vma_lock_flags(unsigned tmp = end; error = mlock_fixup(&vmi, vma, &prev, nstart, tmp, newflags); if (error) - break; + return error; + tmp = vma_iter_end(&vmi); nstart = tmp; }

- if (vma_iter_end(&vmi) < end) + if (tmp < end) return -ENOMEM;

- return error; + return 0; }

/* _

Patches currently in -mm which might be from Liam.Howlett@oracle.com are

mm-mlock-fix-vma-iterator-conversion-of-apply_vma_lock_flags.patch