Merge tag 'mm-hotfixes-stable-2023-01-16-15-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "21 hotfixes. Thirteen of these address pre-6.1 issues and hence have
  the cc:stable tag"

* tag 'mm-hotfixes-stable-2023-01-16-15-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (21 commits)
  init/Kconfig: fix typo (usafe -> unsafe)
  nommu: fix split_vma() map_count error
  nommu: fix do_munmap() error path
  nommu: fix memory leak in do_mmap() error path
  MAINTAINERS: update Robert Foss' email address
  proc: fix PIE proc-empty-vm, proc-pid-vm tests
  mm: update mmap_sem comments to refer to mmap_lock
  include/linux/mm: fix release_pages_arg kernel doc comment
  lib/win_minmax: use /* notation for regular comments
  kasan: mark kasan_kunit_executing as static
  nilfs2: fix general protection fault in nilfs_btree_insert()
  Docs/admin-guide/mm/zswap: remove zsmalloc's lack of writeback warning
  mm/hugetlb: pre-allocate pgtable pages for uffd wr-protects
  hugetlb: unshare some PMDs when splitting VMAs
  mm: fix vma->anon_name memory leak for anonymous shmem VMAs
  mm/shmem: restore SHMEM_HUGE_DENY precedence over MADV_COLLAPSE
  mm/MADV_COLLAPSE: don't expand collapse when vm_end is past requested end
  mm/userfaultfd: enable writenotify while userfaultfd-wp is enabled for a VMA
  mm/khugepaged: fix collapse_pte_mapped_thp() to allow anon_vma
  mm/hugetlb: fix uffd-wp handling for migration entries in hugetlb_change_protection()
  ...

1 files changed, 6 insertions, 3 deletions

diff --git a/mm/nommu.c b/mm/nommu.c
index 214c70e1d059..5b83938ecb67 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -559,7 +559,6 @@ void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas)
 
 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_state *mas, struct mm_struct *mm,
 	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);
@@ -1240,6 +1240,7 @@ share:
 error_just_free:
 	up_write(&nommu_region_sem);
 error:
+	mas_destroy(&mas);
 	if (region->vm_file)
 		fput(region->vm_file);
 	kmem_cache_free(vm_region_jar, region);
@@ -1250,7 +1251,6 @@ error:
 
 sharing_violation:
 	up_write(&nommu_region_sem);
-	mas_destroy(&mas);
 	pr_warn("Attempt to share mismatched mappings\n");
 	ret = -EINVAL;
 	goto error;
@@ -1347,6 +1347,7 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
 	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, struct vm_area_struct *vma,
 	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:
@@ -1509,7 +1511,8 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list
 erase_whole_vma:
 	if (delete_vma_from_mm(vma))
 		ret = -ENOMEM;
-	delete_vma(mm, vma);
+	else
+		delete_vma(mm, vma);
 	return ret;
 }