mm: check for no mmaps in exit_mmap()

[sfrench/cifs-2.6.git] / mm / mmap.c

diff --git a/mm/mmap.c b/mm/mmap.c
index d4855a682ab622863f85352a5353bd45fa1440e4..a910c045cfd4241601306257c8822bda7f1ee05a 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -3,7 +3,7 @@
  *
  * Written by obz.
  *
- * Address space accounting code       <alan@redhat.com>
+ * Address space accounting code       <alan@lxorguk.ukuu.org.uk>
  */
 
 #include <linux/slab.h>
@@ -413,7 +413,7 @@ void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
 
 static void __vma_link_file(struct vm_area_struct *vma)
 {
-       struct file * file;
+       struct file *file;
 
        file = vma->vm_file;
        if (file) {
@@ -474,11 +474,10 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
  * insert vm structure into list and rbtree and anon_vma,
  * but it has already been inserted into prio_tree earlier.
  */
-static void
-__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
+static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma)
 {
-       struct vm_area_struct * __vma, * prev;
-       struct rb_node ** rb_link, * rb_parent;
+       struct vm_area_struct *__vma, *prev;
+       struct rb_node **rb_link, *rb_parent;
 
        __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
        BUG_ON(__vma && __vma->vm_start < vma->vm_end);
@@ -908,7 +907,7 @@ void vm_stat_account(struct mm_struct *mm, unsigned long flags,
  * The caller must hold down_write(current->mm->mmap_sem).
  */
 
-unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
+unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
                        unsigned long len, unsigned long prot,
                        unsigned long flags, unsigned long pgoff)
 {
@@ -1464,7 +1463,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
 EXPORT_SYMBOL(get_unmapped_area);
 
 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */
-struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
+struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
 {
        struct vm_area_struct *vma = NULL;
 
@@ -1507,7 +1506,7 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr,
                        struct vm_area_struct **pprev)
 {
        struct vm_area_struct *vma = NULL, *prev = NULL;
-       struct rb_node * rb_node;
+       struct rb_node *rb_node;
        if (!mm)
                goto out;
 
@@ -1541,7 +1540,7 @@ out:
  * update accounting. This is shared with both the
  * grow-up and grow-down cases.
  */
-static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow)
+static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow)
 {
        struct mm_struct *mm = vma->vm_mm;
        struct rlimit *rlim = current->signal->rlim;
@@ -2091,6 +2090,9 @@ void exit_mmap(struct mm_struct *mm)
        arch_exit_mmap(mm);
        mmu_notifier_release(mm);
 
+       if (!mm->mmap)  /* Can happen if dup_mmap() received an OOM */
+               return;
+
        if (mm->locked_vm) {
                vma = mm->mmap;
                while (vma) {
@@ -2103,7 +2105,7 @@ void exit_mmap(struct mm_struct *mm)
        lru_add_drain();
        flush_cache_mm(mm);
        tlb = tlb_gather_mmu(mm, 1);
-       /* Don't update_hiwater_rss(mm) here, do_exit already did */
+       /* update_hiwater_rss(mm) here? but nobody should be looking */
        /* Use -1 here to ensure all VMAs in the mm are unmapped */
        end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL);
        vm_unacct_memory(nr_accounted);