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From: YueHaibing <yuehaibing@huawei.com>
To: <akpm@linux-foundation.org>, <mst@redhat.com>,
	<keescook@chromium.org>, <kirill.shutemov@linux.intel.com>
Cc: <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	YueHaibing <yuehaibing@huawei.com>
Subject: [PATCH -next] mm/gup_benchmark: Fix unsigned comparison to zero in __gup_benchmark_ioctl
Date: Fri, 21 Sep 2018 17:50:15 +0800	[thread overview]
Message-ID: <20180921095015.26088-1-yuehaibing@huawei.com> (raw)

get_user_pages_fast will return negative value if no pages were pinned,
then be converted to a unsigned, which is compared to zero, giving
the wrong result.

Fixes: 09e35a4a1ca8 ("mm/gup_benchmark: handle gup failures")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
 mm/gup_benchmark.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
index 6a47370..7405c9d8 100644
--- a/mm/gup_benchmark.c
+++ b/mm/gup_benchmark.c
@@ -19,7 +19,8 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
 		struct gup_benchmark *gup)
 {
 	ktime_t start_time, end_time;
-	unsigned long i, nr, nr_pages, addr, next;
+	unsigned long i, nr_pages, addr, next;
+	int nr;
 	struct page **pages;
 
 	nr_pages = gup->size / PAGE_SIZE;
-- 
2.7.0



WARNING: multiple messages have this Message-ID (diff)
From: YueHaibing <yuehaibing@huawei.com>
To: akpm@linux-foundation.org, mst@redhat.com, keescook@chromium.org,
	kirill.shutemov@linux.intel.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	YueHaibing <yuehaibing@huawei.com>
Subject: [PATCH -next] mm/gup_benchmark: Fix unsigned comparison to zero in __gup_benchmark_ioctl
Date: Fri, 21 Sep 2018 17:50:15 +0800	[thread overview]
Message-ID: <20180921095015.26088-1-yuehaibing@huawei.com> (raw)

get_user_pages_fast will return negative value if no pages were pinned,
then be converted to a unsigned, which is compared to zero, giving
the wrong result.

Fixes: 09e35a4a1ca8 ("mm/gup_benchmark: handle gup failures")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
 mm/gup_benchmark.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/gup_benchmark.c b/mm/gup_benchmark.c
index 6a47370..7405c9d8 100644
--- a/mm/gup_benchmark.c
+++ b/mm/gup_benchmark.c
@@ -19,7 +19,8 @@ static int __gup_benchmark_ioctl(unsigned int cmd,
 		struct gup_benchmark *gup)
 {
 	ktime_t start_time, end_time;
-	unsigned long i, nr, nr_pages, addr, next;
+	unsigned long i, nr_pages, addr, next;
+	int nr;
 	struct page **pages;
 
 	nr_pages = gup->size / PAGE_SIZE;
-- 
2.7.0

             reply	other threads:[~2018-09-21  9:50 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-21  9:50 YueHaibing [this message]
2018-09-21  9:50 ` [PATCH -next] mm/gup_benchmark: Fix unsigned comparison to zero in __gup_benchmark_ioctl YueHaibing

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