The patch titled Subject: nommu: fix split_vma() map_count error has been added to the -mm mm-hotfixes-unstable branch. Its filename is nommu-fix-split_vma-map_count-error.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 Howlett liam.howlett@oracle.com Subject: nommu: fix split_vma() map_count error Date: Mon, 9 Jan 2023 20:58:20 +0000

During the maple tree conversion of nommu, an error in counting the VMAs was introduced by counting the existing VMA again. The counting used to be decremented by one and incremented by two, but now it only increments by two. Fix the counting error by moving the increment outside the setup_vma_to_mm() function to the callers.

Link: https://lkml.kernel.org/r/20230109205809.956325-1-Liam.Howlett@oracle.com Fixes: 8220543df148 ("nommu: remove uses of VMA linked list") Signed-off-by: Liam R. Howlett Liam.Howlett@oracle.com Cc: Matthew Wilcox (Oracle) willy@infradead.org Cc: Vlastimil Babka vbabka@suse.cz Cc: Yu Zhao yuzhao@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/nommu.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

--- a/mm/nommu.c~nommu-fix-split_vma-map_count-error +++ a/mm/nommu.c @@ -559,7 +559,6 @@ void vma_mas_remove(struct vm_area_struc

static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm) { - mm->map_count++; vma->vm_mm = mm;

/* add the VMA to the mapping */ @@ -587,6 +586,7 @@ static void mas_add_vma_to_mm(struct ma_ BUG_ON(!vma->vm_region);

setup_vma_to_mm(vma, mm); + mm->map_count++;

/* add the VMA to the tree */ vma_mas_store(vma, mas); @@ -1347,6 +1347,7 @@ int split_vma(struct mm_struct *mm, stru if (vma->vm_file) return -ENOMEM;

+ mm = vma->vm_mm; if (mm->map_count >= sysctl_max_map_count) return -ENOMEM;

@@ -1398,6 +1399,7 @@ int split_vma(struct mm_struct *mm, stru mas_set_range(&mas, vma->vm_start, vma->vm_end - 1); mas_store(&mas, vma); vma_mas_store(new, &mas); + mm->map_count++; return 0;

err_mas_preallocate: _

Patches currently in -mm which might be from liam.howlett@oracle.com are

nommu-fix-memory-leak-in-do_mmap-error-path.patch nommu-fix-do_munmap-error-path.patch nommu-fix-split_vma-map_count-error.patch maple_tree-remove-gfp_zero-from-kmem_cache_alloc-and-kmem_cache_alloc_bulk.patch