The patch titled
hugetlb: prepare_hugepage_range check offset too
has been added to the -mm tree. Its filename is
hugetlb-prepare_hugepage_range-check-offset-too.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: hugetlb: prepare_hugepage_range check offset too
From: Hugh Dickins <hugh@xxxxxxxxxxx>
(David:)
If hugetlbfs_file_mmap() returns a failure to do_mmap_pgoff() - for example,
because the given file offset is not hugepage aligned - then do_mmap_pgoff
will go to the unmap_and_free_vma backout path.
But at this stage the vma hasn't been marked as hugepage, and the backout path
will call unmap_region() on it. That will eventually call down to the
non-hugepage version of unmap_page_range(). On ppc64, at least, that will
cause serious problems if there are any existing hugepage pagetable entries in
the vicinity - for example if there are any other hugepage mappings under the
same PUD. unmap_page_range() will trigger a bad_pud() on the hugepage pud
entries. I suspect this will also cause bad problems on ia64, though I don't
have a machine to test it on.
(Hugh:)
prepare_hugepage_range() should check file offset alignment when it checks
virtual address and length, to stop MAP_FIXED with a bad huge offset from
unmapping before it fails further down. PowerPC should apply the same
prepare_hugepage_range alignment checks as ia64 and all the others do.
Then none of the alignment checks in hugetlbfs_file_mmap are required (nor
is the check for too small a mapping); but even so, move up setting of
VM_HUGETLB and add a comment to warn of what David Gibson discovered - if
hugetlbfs_file_mmap fails before setting it, do_mmap_pgoff's unmap_region
when unwinding from error will go the non-huge way, which may cause bad
behaviour on architectures (powerpc and ia64) which segregate their huge
mappings into a separate region of the address space.
Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Cc: "Luck, Tony" <tony.luck@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Acked-by: Adam Litke <agl@xxxxxxxxxx>
Acked-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
arch/ia64/mm/hugetlbpage.c | 4 +++-
arch/powerpc/mm/hugetlbpage.c | 8 ++++++--
fs/hugetlbfs/inode.c | 21 ++++++++-------------
include/linux/hugetlb.h | 10 +++++++---
mm/mmap.c | 2 +-
5 files changed, 25 insertions(+), 20 deletions(-)
diff -puN arch/ia64/mm/hugetlbpage.c~hugetlb-prepare_hugepage_range-check-offset-too arch/ia64/mm/hugetlbpage.c
--- a/arch/ia64/mm/hugetlbpage.c~hugetlb-prepare_hugepage_range-check-offset-too
+++ a/arch/ia64/mm/hugetlbpage.c
@@ -70,8 +70,10 @@ huge_pte_offset (struct mm_struct *mm, u
* Don't actually need to do any preparation, but need to make sure
* the address is in the right region.
*/
-int prepare_hugepage_range(unsigned long addr, unsigned long len)
+int prepare_hugepage_range(unsigned long addr, unsigned long len, pgoff_t pgoff)
{
+ if (pgoff & (~HPAGE_MASK >> PAGE_SHIFT))
+ return -EINVAL;
if (len & ~HPAGE_MASK)
return -EINVAL;
if (addr & ~HPAGE_MASK)
diff -puN arch/powerpc/mm/hugetlbpage.c~hugetlb-prepare_hugepage_range-check-offset-too arch/powerpc/mm/hugetlbpage.c
--- a/arch/powerpc/mm/hugetlbpage.c~hugetlb-prepare_hugepage_range-check-offset-too
+++ a/arch/powerpc/mm/hugetlbpage.c
@@ -491,11 +491,15 @@ static int open_high_hpage_areas(struct
return 0;
}
-int prepare_hugepage_range(unsigned long addr, unsigned long len)
+int prepare_hugepage_range(unsigned long addr, unsigned long len, pgoff_t pgoff)
{
int err = 0;
- if ( (addr+len) < addr )
+ if (pgoff & (~HPAGE_MASK >> PAGE_SHIFT))
+ return -EINVAL;
+ if (len & ~HPAGE_MASK)
+ return -EINVAL;
+ if (addr & ~HPAGE_MASK)
return -EINVAL;
if (addr < 0x100000000UL)
diff -puN fs/hugetlbfs/inode.c~hugetlb-prepare_hugepage_range-check-offset-too fs/hugetlbfs/inode.c
--- a/fs/hugetlbfs/inode.c~hugetlb-prepare_hugepage_range-check-offset-too
+++ a/fs/hugetlbfs/inode.c
@@ -62,24 +62,19 @@ static int hugetlbfs_file_mmap(struct fi
loff_t len, vma_len;
int ret;
- if (vma->vm_pgoff & (HPAGE_SIZE / PAGE_SIZE - 1))
- return -EINVAL;
-
- if (vma->vm_start & ~HPAGE_MASK)
- return -EINVAL;
-
- if (vma->vm_end & ~HPAGE_MASK)
- return -EINVAL;
-
- if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
- return -EINVAL;
+ /*
+ * vma alignment has already been checked by prepare_hugepage_range.
+ * If you add any error returns here, do so after setting VM_HUGETLB,
+ * so is_vm_hugetlb_page tests below unmap_region go the right way
+ * when do_mmap_pgoff unwinds (may be important on powerpc and ia64).
+ */
+ vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
+ vma->vm_ops = &hugetlb_vm_ops;
vma_len = (loff_t)(vma->vm_end - vma->vm_start);
mutex_lock(&inode->i_mutex);
file_accessed(file);
- vma->vm_flags |= VM_HUGETLB | VM_RESERVED;
- vma->vm_ops = &hugetlb_vm_ops;
ret = -ENOMEM;
len = vma_len + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
diff -puN include/linux/hugetlb.h~hugetlb-prepare_hugepage_range-check-offset-too include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~hugetlb-prepare_hugepage_range-check-offset-too
+++ a/include/linux/hugetlb.h
@@ -60,8 +60,11 @@ void hugetlb_free_pgd_range(struct mmu_g
* If the arch doesn't supply something else, assume that hugepage
* size aligned regions are ok without further preparation.
*/
-static inline int prepare_hugepage_range(unsigned long addr, unsigned long len)
+static inline int prepare_hugepage_range(unsigned long addr, unsigned long len,
+ pgoff_t pgoff)
{
+ if (pgoff & (~HPAGE_MASK >> PAGE_SHIFT))
+ return -EINVAL;
if (len & ~HPAGE_MASK)
return -EINVAL;
if (addr & ~HPAGE_MASK)
@@ -69,7 +72,8 @@ static inline int prepare_hugepage_range
return 0;
}
#else
-int prepare_hugepage_range(unsigned long addr, unsigned long len);
+int prepare_hugepage_range(unsigned long addr, unsigned long len,
+ pgoff_t pgoff);
#endif
#ifndef ARCH_HAS_SETCLEAR_HUGE_PTE
@@ -107,7 +111,7 @@ static inline unsigned long hugetlb_tota
#define hugetlb_report_meminfo(buf) 0
#define hugetlb_report_node_meminfo(n, buf) 0
#define follow_huge_pmd(mm, addr, pmd, write) NULL
-#define prepare_hugepage_range(addr, len) (-EINVAL)
+#define prepare_hugepage_range(addr,len,pgoff) (-EINVAL)
#define pmd_huge(x) 0
#define is_hugepage_only_range(mm, addr, len) 0
#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
diff -puN mm/mmap.c~hugetlb-prepare_hugepage_range-check-offset-too mm/mmap.c
--- a/mm/mmap.c~hugetlb-prepare_hugepage_range-check-offset-too
+++ a/mm/mmap.c
@@ -1379,7 +1379,7 @@ get_unmapped_area(struct file *file, uns
* Check if the given range is hugepage aligned, and
* can be made suitable for hugepages.
*/
- ret = prepare_hugepage_range(addr, len);
+ ret = prepare_hugepage_range(addr, len, pgoff);
} else {
/*
* Ensure that a normal request is not falling in a
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
hugetlb-prepare_hugepage_range-check-offset-too.patch
__unmap_hugepage_range-add-comment.patch
shared-page-table-for-hugetlb-page-v4.patch
htlb-forget-rss-with-pt-sharing.patch
mlock-cleanup.patch
honour-mnt_noexec-for-access.patch
generic-bug-implementation.patch
generic-bug-for-i386.patch
generic-bug-for-x86-64.patch
bug-test-1.patch
tty-switch-to-ktermios-powerpc-fix.patch
-
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