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ksm: check for ERR_PTR from follow_page()

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The follow_page() function can potentially return -EFAULT so I added
checks for this.

Also I silenced an uninitialized variable warning on my version of gcc
(version 4.3.2).

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Izik Eidus <ieidus@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Dan Carpenter 2010-04-23 13:18:10 -04:00 committed by Linus Torvalds
parent 453dc65931
commit 22eccdd7d2
1 changed files with 6 additions and 6 deletions
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12
mm/ksm.c
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@ -365,7 +365,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
do { do {
cond_resched(); cond_resched();
page = follow_page(vma, addr, FOLL_GET); page = follow_page(vma, addr, FOLL_GET);
if (!page) if (IS_ERR_OR_NULL(page))
break; break;
if (PageKsm(page)) if (PageKsm(page))
ret = handle_mm_fault(vma->vm_mm, vma, addr, ret = handle_mm_fault(vma->vm_mm, vma, addr,
@ -447,7 +447,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
goto out; goto out;
page = follow_page(vma, addr, FOLL_GET); page = follow_page(vma, addr, FOLL_GET);
if (!page) if (IS_ERR_OR_NULL(page))
goto out; goto out;
if (PageAnon(page)) { if (PageAnon(page)) {
flush_anon_page(vma, page, addr); flush_anon_page(vma, page, addr);
@ -1086,7 +1086,7 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
cond_resched(); cond_resched();
tree_rmap_item = rb_entry(*new, struct rmap_item, node); tree_rmap_item = rb_entry(*new, struct rmap_item, node);
tree_page = get_mergeable_page(tree_rmap_item); tree_page = get_mergeable_page(tree_rmap_item);
if (!tree_page) if (IS_ERR_OR_NULL(tree_page))
return NULL; return NULL;
/* /*
@ -1294,7 +1294,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
if (ksm_test_exit(mm)) if (ksm_test_exit(mm))
break; break;
*page = follow_page(vma, ksm_scan.address, FOLL_GET); *page = follow_page(vma, ksm_scan.address, FOLL_GET);
if (*page && PageAnon(*page)) { if (!IS_ERR_OR_NULL(*page) && PageAnon(*page)) {
flush_anon_page(vma, *page, ksm_scan.address); flush_anon_page(vma, *page, ksm_scan.address);
flush_dcache_page(*page); flush_dcache_page(*page);
rmap_item = get_next_rmap_item(slot, rmap_item = get_next_rmap_item(slot,
@ -1308,7 +1308,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
up_read(&mm->mmap_sem); up_read(&mm->mmap_sem);
return rmap_item; return rmap_item;
} }
if (*page) if (!IS_ERR_OR_NULL(*page))
put_page(*page); put_page(*page);
ksm_scan.address += PAGE_SIZE; ksm_scan.address += PAGE_SIZE;
cond_resched(); cond_resched();
@ -1367,7 +1367,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page)
static void ksm_do_scan(unsigned int scan_npages) static void ksm_do_scan(unsigned int scan_npages)
{ {
struct rmap_item *rmap_item; struct rmap_item *rmap_item;
struct page *page; struct page *uninitialized_var(page);
while (scan_npages--) { while (scan_npages--) {
cond_resched(); cond_resched();