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    Subject[PATCH 1/3] mm: use long type for page counts in mm_populate() and get_user_pages()
    Date
    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>

    ---
    include/linux/hugetlb.h | 6 +++---
    include/linux/mm.h | 14 +++++++-------
    mm/hugetlb.c | 10 +++++-----
    mm/memory.c | 14 +++++++-------
    mm/mlock.c | 5 +++--
    5 files changed, 25 insertions(+), 24 deletions(-)

    diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
    index 0c80d3f57a5b..fc6ed17cfd17 100644
    --- 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 *, long *, long, unsigned int flags);
    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 a224430578f0..d5716094f191 100644
    --- a/include/linux/mm.h
    +++ b/include/linux/mm.h
    @@ -1040,13 +1040,13 @@ 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, long len, 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, 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 4f3ea0b1e57c..4ad07221ce60 100644
    --- a/mm/hugetlb.c
    +++ b/mm/hugetlb.c
    @@ -2924,14 +2924,14 @@ 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, long *length, long i,
    + unsigned int flags)
    {
    unsigned long pfn_offset;
    unsigned long vaddr = *position;
    - int remainder = *length;
    + long remainder = *length;
    struct hstate *h = hstate_vma(vma);

    spin_lock(&mm->page_table_lock);
    diff --git a/mm/memory.c b/mm/memory.c
    index f56683208e7f..381b78c20d84 100644
    --- a/mm/memory.c
    +++ b/mm/memory.c
    @@ -1673,12 +1673,12 @@ 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, 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)
    @@ -1977,8 +1977,8 @@ 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,
    +long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
    + unsigned long start, 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 b1647fbd6bce..e1fa9e4b0a66 100644
    --- 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;
    + long nr_pages = (end - start) / PAGE_SIZE;
    int gup_flags;

    VM_BUG_ON(start & ~PAGE_MASK);
    @@ -378,7 +378,7 @@ 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));
    @@ -421,6 +421,7 @@ int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
    ret = __mlock_posix_error_return(ret);
    break;
    }
    + VM_BUG_ON(!ret);
    nend = nstart + ret * PAGE_SIZE;
    ret = 0;
    }
    --
    1.8.1

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