From: Dan Carpenter <error27@gmail.com>
To: Izik Eidus <ieidus@redhat.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>,
Andrea Arcangeli <aarcange@redhat.com>,
Rik van Riel <riel@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
kernel-janitors@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>
Subject: [patch] ksm: check for ERR_PTR from follow_page()
Date: Wed, 21 Apr 2010 12:27:59 +0200 [thread overview]
Message-ID: <20100421102759.GA29647@bicker> (raw)
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>
---
I'm not very familiar with this code, so handle with care.
diff --git a/mm/ksm.c b/mm/ksm.c
index 8cdfc2a..956880f 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)
do {
cond_resched();
page = follow_page(vma, addr, FOLL_GET);
- if (!page)
+ if (IS_ERR_OR_NULL(page))
break;
if (PageKsm(page))
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;
page = follow_page(vma, addr, FOLL_GET);
- if (!page)
+ if (IS_ERR_OR_NULL(page))
goto out;
if (PageAnon(page)) {
flush_anon_page(vma, page, addr);
@@ -1086,7 +1086,7 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item,
cond_resched();
tree_rmap_item = rb_entry(*new, struct rmap_item, node);
tree_page = get_mergeable_page(tree_rmap_item);
- if (!tree_page)
+ if (IS_ERR_OR_NULL(tree_page))
return NULL;
/*
@@ -1294,7 +1294,7 @@ next_mm:
if (ksm_test_exit(mm))
break;
*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_dcache_page(*page);
rmap_item = get_next_rmap_item(slot,
@@ -1308,7 +1308,7 @@ next_mm:
up_read(&mm->mmap_sem);
return rmap_item;
}
- if (*page)
+ if (!IS_ERR_OR_NULL(*page))
put_page(*page);
ksm_scan.address += PAGE_SIZE;
cond_resched();
@@ -1367,7 +1367,7 @@ next_mm:
static void ksm_do_scan(unsigned int scan_npages)
{
struct rmap_item *rmap_item;
- struct page *page;
+ struct page *uninitialized_var(page);
while (scan_npages--) {
cond_resched();
--
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next reply other threads:[~2010-04-21 10:29 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-21 10:27 Dan Carpenter [this message]
2010-04-21 15:24 ` [patch] ksm: check for ERR_PTR from follow_page() Rik van Riel
2010-04-21 17:46 ` Andrea Arcangeli
2010-04-21 20:53 ` Johannes Weiner
2010-04-21 20:58 ` Andrea Arcangeli
2010-04-21 21:10 ` Johannes Weiner
2010-04-21 23:51 ` Izik Eidus
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