From: "Américo Wang" <xiyou.wangcong@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@osdl.org>,
Nick Piggin <nickpiggin@yahoo.com.au>
Subject: [Patch] mm: fix null pointer dereference in vm_normal_page()
Date: Wed, 18 Feb 2009 20:56:49 +0800 [thread overview]
Message-ID: <20090218125649.GU7272@hack.private> (raw)
One usage of vm_normal_page() is:
struct page *page = vm_normal_page(gate_vma, start, *pte);
where gate_vma is returned by get_gate_vma() which can be NULL.
So let vm_normal_page return NULL when vma is NULL.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
---
diff --git a/mm/memory.c b/mm/memory.c
index baa999e..e428aa6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -493,6 +493,9 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
{
unsigned long pfn = pte_pfn(pte);
+ if (!vma)
+ return NULL;
+
if (HAVE_PTE_SPECIAL) {
if (likely(!pte_special(pte)))
goto check_pfn;
--
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next reply other threads:[~2009-02-18 12:56 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-18 12:56 Américo Wang [this message]
2009-02-18 17:23 ` Johannes Weiner
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