mm: use long type for page counts in mm_populate() and get_user_pages()

Use long type for page counts in mm_populate() so as to avoid integer
overflow when running the following test code:

int main(void) {
  void *p = mmap(NULL, 0x100000000000, PROT_READ,
                 MAP_PRIVATE | MAP_ANON, -1, 0);
  printf("p: %p\n", p);
  mlockall(MCL_CURRENT);
  printf("done\n");
  return 0;
}

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 0c80d3f..eedc334 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -43,9 +43,9 @@ int hugetlb_mempolicy_sysctl_handler(struct ctl_table *, int,
 #endif
 
 int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *);
-int follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
-                       struct page **, struct vm_area_struct **,
-                       unsigned long *, int *, int, unsigned int flags);
+long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *,
+                        struct page **, struct vm_area_struct **,
+                        unsigned long *, unsigned long *, long, unsigned int);
 void unmap_hugepage_range(struct vm_area_struct *,
                          unsigned long, unsigned long, struct page *);
 void __unmap_hugepage_range_final(struct mmu_gather *tlb,

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 97da030..87b0ef2 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1013,13 +1013,14 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *
 extern int access_remote_vm(struct mm_struct *mm, unsigned long addr,
                void *buf, int len, int write);
 
-int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                    unsigned long start, int len, unsigned int foll_flags,
-                    struct page **pages, struct vm_area_struct **vmas,
-                    int *nonblocking);
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                       unsigned long start, int nr_pages, int write, int force,
-                       struct page **pages, struct vm_area_struct **vmas);
+long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                     unsigned long start, unsigned long nr_pages,
+                     unsigned int foll_flags, struct page **pages,
+                     struct vm_area_struct **vmas, int *nonblocking);
+long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                   unsigned long start, unsigned long nr_pages,
+                   int write, int force, struct page **pages,
+                   struct vm_area_struct **vmas);
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
                        struct page **pages);
 struct kvec;

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e14a8c7..cdb64e4 100644 (file)
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2920,14 +2920,14 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address,
        return NULL;
 }
 
-int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
-                       struct page **pages, struct vm_area_struct **vmas,
-                       unsigned long *position, int *length, int i,
-                       unsigned int flags)
+long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
+                        struct page **pages, struct vm_area_struct **vmas,
+                        unsigned long *position, unsigned long *nr_pages,
+                        long i, unsigned int flags)
 {
        unsigned long pfn_offset;
        unsigned long vaddr = *position;
-       int remainder = *length;
+       unsigned long remainder = *nr_pages;
        struct hstate *h = hstate_vma(vma);
 
        spin_lock(&mm->page_table_lock);
@@ -2997,7 +2997,7 @@ same_page:
                }
        }
        spin_unlock(&mm->page_table_lock);
-       *length = remainder;
+       *nr_pages = remainder;
        *position = vaddr;
 
        return i ? i : -EFAULT;

diff --git a/mm/memory.c b/mm/memory.c
index 7bd22a6..bc929db 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1677,15 +1677,15 @@ static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long add
  * instead of __get_user_pages. __get_user_pages should be used only if
  * you need some special @gup_flags.
  */
-int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                    unsigned long start, int nr_pages, unsigned int gup_flags,
-                    struct page **pages, struct vm_area_struct **vmas,
-                    int *nonblocking)
+long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+               unsigned long start, unsigned long nr_pages,
+               unsigned int gup_flags, struct page **pages,
+               struct vm_area_struct **vmas, int *nonblocking)
 {
-       int i;
+       long i;
        unsigned long vm_flags;
 
-       if (nr_pages <= 0)
+       if (!nr_pages)
                return 0;
 
        VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
@@ -1981,9 +1981,9 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
  *
  * See also get_user_pages_fast, for performance critical applications.
  */
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-               unsigned long start, int nr_pages, int write, int force,
-               struct page **pages, struct vm_area_struct **vmas)
+long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+               unsigned long start, unsigned long nr_pages, int write,
+               int force, struct page **pages, struct vm_area_struct **vmas)
 {
        int flags = FOLL_TOUCH;
 

diff --git a/mm/mlock.c b/mm/mlock.c
index 38db3b0..e6638f5 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -160,7 +160,7 @@ long __mlock_vma_pages_range(struct vm_area_struct *vma,
 {
        struct mm_struct *mm = vma->vm_mm;
        unsigned long addr = start;
-       int nr_pages = (end - start) / PAGE_SIZE;
+       unsigned long nr_pages = (end - start) / PAGE_SIZE;
        int gup_flags;
 
        VM_BUG_ON(start & ~PAGE_MASK);
@@ -382,7 +382,7 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
        unsigned long end, nstart, nend;
        struct vm_area_struct *vma = NULL;
        int locked = 0;
-       int ret = 0;
+       long ret = 0;
 
        VM_BUG_ON(start & ~PAGE_MASK);
        VM_BUG_ON(len != PAGE_ALIGN(len));

diff --git a/mm/nommu.c b/mm/nommu.c
index 87854a5..6ab7066 100644 (file)
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -140,10 +140,10 @@ unsigned int kobjsize(const void *objp)
        return PAGE_SIZE << compound_order(page);
 }
 
-int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-                    unsigned long start, int nr_pages, unsigned int foll_flags,
-                    struct page **pages, struct vm_area_struct **vmas,
-                    int *retry)
+long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                     unsigned long start, unsigned long nr_pages,
+                     unsigned int foll_flags, struct page **pages,
+                     struct vm_area_struct **vmas, int *nonblocking)
 {
        struct vm_area_struct *vma;
        unsigned long vm_flags;
@@ -190,9 +190,10 @@ finish_or_fault:
  *   slab page or a secondary page from a compound page
  * - don't permit access to VMAs that don't support it, such as I/O mappings
  */
-int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
-       unsigned long start, int nr_pages, int write, int force,
-       struct page **pages, struct vm_area_struct **vmas)
+long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
+                   unsigned long start, unsigned long nr_pages,
+                   int write, int force, struct page **pages,
+                   struct vm_area_struct **vmas)
 {
        int flags = 0;