The patch titled
Subject: mm: make sure all file VMAs have ->vm_ops set
has been removed from the -mm tree. Its filename was
mm-make-sure-all-file-vmas-have-vm_ops-set.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm: make sure all file VMAs have ->vm_ops set
We rely on vma->vm_ops == NULL to detect anonymous VMA: see
vma_is_anonymous(), but some drivers doesn't set ->vm_ops.
As a result we can end up with anonymous page in private file mapping.
That should not lead to serious misbehaviour, but nevertheless is wrong.
Let's fix by setting up dummy ->vm_ops for file mmapping if f_op->mmap()
didn't set its own.
The patch also adds sanity check into __vma_link_rb(). It will help
catch broken VMAs which inserted directly into mm_struct via
insert_vm_struct().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mmap.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff -puN mm/mmap.c~mm-make-sure-all-file-vmas-have-vm_ops-set mm/mmap.c
--- a/mm/mmap.c~mm-make-sure-all-file-vmas-have-vm_ops-set
+++ a/mm/mmap.c
@@ -612,6 +612,8 @@ static unsigned long count_vma_pages_ran
void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
struct rb_node **rb_link, struct rb_node *rb_parent)
{
+ WARN_ONCE(vma->vm_file && !vma->vm_ops, "missing vma->vm_ops");
+
/* Update tracking information for the gap following the new vma. */
if (vma->vm_next)
vma_gap_update(vma->vm_next);
@@ -1636,6 +1638,12 @@ unsigned long mmap_region(struct file *f
*/
WARN_ON_ONCE(addr != vma->vm_start);
+ /* All file mapping must have ->vm_ops set */
+ if (!vma->vm_ops) {
+ static const struct vm_operations_struct dummy_ops = {};
+ vma->vm_ops = &dummy_ops;
+ }
+
addr = vma->vm_start;
vm_flags = vma->vm_flags;
} else if (vm_flags & VM_SHARED) {
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-on-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
mm-support-madvisemadv_free-fix-3.patch
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