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authorHugh Dickins <hugh@veritas.com>2006-11-14 02:03:32 -0800
committerLinus Torvalds <torvalds@woody.osdl.org>2006-11-14 09:09:27 -0800
commit68589bc353037f233fe510ad9ff432338c95db66 (patch)
treededc58ff66134f54796642917e2a2a26ac6802b0
parent69ae9e3ee4ce99140a7db424bebf55d8d180da2f (diff)
[PATCH] hugetlb: prepare_hugepage_range check offset too
(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@veritas.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: "David S. Miller" <davem@davemloft.net> Acked-by: Adam Litke <agl@us.ibm.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--arch/ia64/mm/hugetlbpage.c4
-rw-r--r--arch/powerpc/mm/hugetlbpage.c8
-rw-r--r--fs/hugetlbfs/inode.c21
-rw-r--r--include/linux/hugetlb.h10
-rw-r--r--mm/mmap.c2
5 files changed, 25 insertions, 20 deletions
diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index eee5c1cfbe32..f3a9585e98a8 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c
@@ -70,8 +70,10 @@ huge_pte_offset (struct mm_struct *mm, unsigned long addr)
* 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 --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index fd68b74c07c3..506d89768d45 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -491,11 +491,15 @@ static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas)
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 --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c
index 0bea6a619e10..7f4756963d05 100644
--- a/fs/hugetlbfs/inode.c
+++ b/fs/hugetlbfs/inode.c
@@ -62,24 +62,19 @@ static int hugetlbfs_file_mmap(struct file *file, struct vm_area_struct *vma)
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 --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 5081d27bfa27..ace64e57e17f 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -60,8 +60,11 @@ void hugetlb_free_pgd_range(struct mmu_gather **tlb, unsigned long addr,
* 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(unsigned long addr, unsigned long len)
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_total_pages(void)
#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 --git a/mm/mmap.c b/mm/mmap.c
index 497e502dfd6b..bdace87d7c01 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1379,7 +1379,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
* 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