+ mm-mmap-undo-mmap-when-mas_preallocate-fails.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/mmap: undo ->mmap() when mas_preallocate() fails
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     mm-mmap-undo-mmap-when-mas_preallocate-fails.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mmap-undo-mmap-when-mas_preallocate-fails.patch

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: Mike Kravetz <mike.kravetz@oracle.com>
Subject: mm/mmap: undo ->mmap() when mas_preallocate() fails
Date: Mon, 17 Oct 2022 19:49:45 -0700

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 deb0f6562884 ("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/20221018024945.415036-1-mike.kravetz@oracle.com
Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/mmap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/mmap.c~mm-mmap-undo-mmap-when-mas_preallocate-fails
+++ a/mm/mmap.c
@@ -2681,7 +2681,7 @@ cannot_expand:
 	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;
 	}
_

Patches currently in -mm which might be from mike.kravetz@oracle.com are

mm-mmap-undo-mmap-when-mas_preallocate-fails.patch
hugetlb-simplify-hugetlb-handling-in-follow_page_mask.patch