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authorDan Carpenter <error27@gmail.com>2010-04-23 13:18:10 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-04-24 14:31:26 -0400
commit22eccdd7d2d94be48ae9b01fef5f52ccbb81dcd5 (patch)
tree346ba02239f0d3a1ed5d1d09fc3d323c29202270 /mm/ksm.c
parent453dc65931915abc61f92e12bba1fc4747ff5542 (diff)
ksm: check for ERR_PTR from follow_page()
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>
Diffstat (limited to 'mm/ksm.c')
-rw-r--r--mm/ksm.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 8cdfc2a1e8bf..956880f2ff49 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -365,7 +365,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
365 do { 365 do {
366 cond_resched(); 366 cond_resched();
367 page = follow_page(vma, addr, FOLL_GET); 367 page = follow_page(vma, addr, FOLL_GET);
368 if (!page) 368 if (IS_ERR_OR_NULL(page))
369 break; 369 break;
370 if (PageKsm(page)) 370 if (PageKsm(page))
371 ret = handle_mm_fault(vma->vm_mm, vma, addr, 371 ret = handle_mm_fault(vma->vm_mm, vma, addr,
@@ -447,7 +447,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
447 goto out; 447 goto out;
448 448
449 page = follow_page(vma, addr, FOLL_GET); 449 page = follow_page(vma, addr, FOLL_GET);
450 if (!page) 450 if (IS_ERR_OR_NULL(page))
451 goto out; 451 goto out;
452 if (PageAnon(page)) { 452 if (PageAnon(page)) {
453 flush_anon_page(vma, page, addr); 453 flush_anon_page(vma, page, addr);
@@ -1086,7 +1086,7 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
1086 cond_resched(); 1086 cond_resched();
1087 tree_rmap_item = rb_entry(*new, struct rmap_item, node); 1087 tree_rmap_item = rb_entry(*new, struct rmap_item, node);
1088 tree_page = get_mergeable_page(tree_rmap_item); 1088 tree_page = get_mergeable_page(tree_rmap_item);
1089 if (!tree_page) 1089 if (IS_ERR_OR_NULL(tree_page))
1090 return NULL; 1090 return NULL;
1091 1091
1092 /* 1092 /*
@@ -1294,7 +1294,7 @@ next_mm:
1294 if (ksm_test_exit(mm)) 1294 if (ksm_test_exit(mm))
1295 break; 1295 break;
1296 *page = follow_page(vma, ksm_scan.address, FOLL_GET); 1296 *page = follow_page(vma, ksm_scan.address, FOLL_GET);
1297 if (*page && PageAnon(*page)) { 1297 if (!IS_ERR_OR_NULL(*page) && PageAnon(*page)) {
1298 flush_anon_page(vma, *page, ksm_scan.address); 1298 flush_anon_page(vma, *page, ksm_scan.address);
1299 flush_dcache_page(*page); 1299 flush_dcache_page(*page);
1300 rmap_item = get_next_rmap_item(slot, 1300 rmap_item = get_next_rmap_item(slot,
@@ -1308,7 +1308,7 @@ next_mm:
1308 up_read(&mm->mmap_sem); 1308 up_read(&mm->mmap_sem);
1309 return rmap_item; 1309 return rmap_item;
1310 } 1310 }
1311 if (*page) 1311 if (!IS_ERR_OR_NULL(*page))
1312 put_page(*page); 1312 put_page(*page);
1313 ksm_scan.address += PAGE_SIZE; 1313 ksm_scan.address += PAGE_SIZE;
1314 cond_resched(); 1314 cond_resched();
@@ -1367,7 +1367,7 @@ next_mm:
1367static void ksm_do_scan(unsigned int scan_npages) 1367static void ksm_do_scan(unsigned int scan_npages)
1368{ 1368{
1369 struct rmap_item *rmap_item; 1369 struct rmap_item *rmap_item;
1370 struct page *page; 1370 struct page *uninitialized_var(page);
1371 1371
1372 while (scan_npages--) { 1372 while (scan_npages--) {
1373 cond_resched(); 1373 cond_resched();