+ mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list.patch added to -mm tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The patch titled
     Subject: fs/hugetlbfs/inode.c: fix bugs in hugetlb_vmtruncate_list()
has been added to the -mm tree.  Its filename is
     mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/SubmitChecklist when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: fs/hugetlbfs/inode.c: fix bugs in hugetlb_vmtruncate_list()

Hillf Danton noticed bugs in the hugetlb_vmtruncate_list routine.  The
argument end is of type pgoff_t.  It was being converted to a vaddr offset
and passed to unmap_hugepage_range.  However, end was also being used as
an argument to the vma_interval_tree_foreach controlling loop.  In
addition, the conversion of end to vaddr offset was incorrect.

hugetlb_vmtruncate_list is called as part of a file truncate or fallocate
hole punch operation.

When truncating a hugetlbfs file, this bug could prevent some pages from
being unmapped.  This is possible if there are multiple vmas mapping the
file, and there is a sufficiently sized hole between the mappings.  The
size of the hole between two vmas (A,B) must be such that the starting
virtual address of B is greater than (ending virtual address of A <<
PAGE_SHIFT).  In this case, the pages in B would not be unmapped.  If
pages are not properly unmapped during truncate, the following BUG is hit:

	kernel BUG at fs/hugetlbfs/inode.c:428!

In the fallocate hole punch case, this bug could prevent pages from being
unmapped as in the truncate case.  However, for hole punch the result is
that unmapped pages will not be removed during the operation.  For hole
punch, it is also possible that more pages than desired will be unmapped. 
This unnecessary unmapping will cause page faults to reestablish the
mappings on subsequent page access.

Fixes: 1bfad99ab (" hugetlbfs: hugetlb_vmtruncate_list() needs to take a range")Reported-by: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>	[4.3]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 fs/hugetlbfs/inode.c |   19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff -puN fs/hugetlbfs/inode.c~mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list fs/hugetlbfs/inode.c
--- a/fs/hugetlbfs/inode.c~mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list
+++ a/fs/hugetlbfs/inode.c
@@ -463,6 +463,7 @@ hugetlb_vmdelete_list(struct rb_root *ro
 	 */
 	vma_interval_tree_foreach(vma, root, start, end ? end : ULONG_MAX) {
 		unsigned long v_offset;
+		unsigned long v_end;
 
 		/*
 		 * Can the expression below overflow on 32-bit arches?
@@ -475,15 +476,17 @@ hugetlb_vmdelete_list(struct rb_root *ro
 		else
 			v_offset = 0;
 
-		if (end) {
-			end = ((end - start) << PAGE_SHIFT) +
-			       vma->vm_start + v_offset;
-			if (end > vma->vm_end)
-				end = vma->vm_end;
-		} else
-			end = vma->vm_end;
+		if (!end)
+			v_end = vma->vm_end;
+		else {
+			v_end = ((end - vma->vm_pgoff) << PAGE_SHIFT)
+							+ vma->vm_start;
+			if (v_end > vma->vm_end)
+				v_end = vma->vm_end;
+		}
 
-		unmap_hugepage_range(vma, vma->vm_start + v_offset, end, NULL);
+		unmap_hugepage_range(vma, vma->vm_start + v_offset, v_end,
+									NULL);
 	}
 }
 
diff -puN /dev/null /dev/null
_

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

mm-hugetlbfs-fix-bugs-in-hugetlb_vmtruncate_list.patch

--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]