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From: Sasha Levin <sasha.levin@oracle.com>
To: akpm@linux-foundation.org
Cc: n-horiguchi@ah.jp.nec.com, aarcange@redhat.com, mgorman@suse.de,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	a.ryabinin@samsung.com, Sasha Levin <sasha.levin@oracle.com>
Subject: [PATCH] mm, hugetlb: correct bit shift in hstate_sizelog
Date: Tue, 21 Oct 2014 14:15:07 -0400	[thread overview]
Message-ID: <1413915307-20536-1-git-send-email-sasha.levin@oracle.com> (raw)

hstate_sizelog() would shift left an int rather than long, triggering
undefined behaviour and passing an incorrect value when the requested
page size was more than 4GB, thus breaking >4GB pages.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
---
 include/linux/hugetlb.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 65e12a2..57e0dfd 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -312,7 +312,8 @@ static inline struct hstate *hstate_sizelog(int page_size_log)
 {
 	if (!page_size_log)
 		return &default_hstate;
-	return size_to_hstate(1 << page_size_log);
+
+	return size_to_hstate(1UL << page_size_log);
 }
 
 static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
-- 
1.7.10.4

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             reply	other threads:[~2014-10-21 18:15 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-21 18:15 Sasha Levin [this message]
2014-10-22  5:42 ` Andrey Ryabinin
2014-10-22 18:44   ` Andrew Morton
2014-10-22 18:50     ` Sasha Levin
2014-10-22 20:13       ` Andrew Morton
2014-10-22 20:26         ` Andrey Ryabinin
2014-10-22 19:04     ` Andrey Ryabinin

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