mm/mmap: undo ->mmap() when mas_preallocate() fails

A memory leak in hugetlb_reserve_pages was reported in [1].  The root
cause was traced to an error path in mmap_region when mas_preallocate()
fails.  In this case, the vma is freed after a successful call to
filesystem specific mmap.  The hugetlbfs mmap routine may allocate data
structures pointed to by m_private_data.  These need to be cleaned up by
the hugetlb vm_ops->close() routine.

The same issue was addressed by commit deb0f65 ("mm/mmap: undo
->mmap() when arch_validate_flags() fails") for the arch_validate_flags()
test.  Go to the same close_and_free_vma label if mas_preallocate() fails.

[1] https://lore.kernel.org/linux-mm/CAKXUXMxf7OiCwbxib7MwfR4M1b5+b3cNTU7n5NV9Zm4967=FPQ@mail.gmail.com/

Link: https://lkml.kernel.org/r/[email protected]
Fixes: d4af56c ("mm: start tracking VMAs with maple tree")
Signed-off-by: Mike Kravetz <[email protected]>
Reported-by: Lukas Bulwahn <[email protected]>
Reviewed-by: Liam R. Howlett <[email protected]>
Cc: Andrii Nakryiko <[email protected]>
Cc: Carlos Llamas <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Muchun Song <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

Author: mjkravetz

mm/mmap.c

@@ -2681,7 +2681,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	if (mas_preallocate(&mas, vma, GFP_KERNEL)) {
 		error = -ENOMEM;
 		if (file)
-			goto unmap_and_free_vma;
+			goto close_and_free_vma;
 		else
 			goto free_vma;
 	}