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* [PATCH] mm: Change count_mm_mlocked_page_nr return type
@ 2019-05-13  2:37 Weikang shi
  2019-05-13  9:15 ` Michal Hocko
  0 siblings, 1 reply; 4+ messages in thread
From: Weikang shi @ 2019-05-13  2:37 UTC (permalink / raw)
  To: linux-mm; +Cc: linux-kernel, swkhack

From: swkhack <swkhack@gmail.com>

In 64-bit machine,the value of "vma->vm_end - vma->vm_start"
maybe negative in 32bit int and the "count >> PAGE_SHIFT"'s result
will be wrong.So change the local variable and return
value to unsigned long will fix the problem.

Signed-off-by: swkhack <swkhack@gmail.com>
---
 mm/mlock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 080f3b364..d614163f5 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -636,11 +636,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
  * is also counted.
  * Return value: previously mlocked page counts
  */
-static int count_mm_mlocked_page_nr(struct mm_struct *mm,
+static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 		unsigned long start, size_t len)
 {
 	struct vm_area_struct *vma;
-	int count = 0;
+	unsigned long count = 0;
 
 	if (mm == NULL)
 		mm = current->mm;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] mm: Change count_mm_mlocked_page_nr return type
  2019-05-13  2:37 [PATCH] mm: Change count_mm_mlocked_page_nr return type Weikang shi
@ 2019-05-13  9:15 ` Michal Hocko
  0 siblings, 0 replies; 4+ messages in thread
From: Michal Hocko @ 2019-05-13  9:15 UTC (permalink / raw)
  To: Weikang shi; +Cc: linux-mm, linux-kernel

On Mon 13-05-19 10:37:01, Weikang shi wrote:
> From: swkhack <swkhack@gmail.com>
> 
> In 64-bit machine,the value of "vma->vm_end - vma->vm_start"
> maybe negative in 32bit int and the "count >> PAGE_SHIFT"'s result
> will be wrong.So change the local variable and return
> value to unsigned long will fix the problem.
> 
> Signed-off-by: swkhack <swkhack@gmail.com>

Fixes: 0cf2f6f6dc60 ("mm: mlock: check against vma for actual mlock() size")

Acked-by: Michal Hocko <mhocko@suse.com>

Most users probably never noticed because large mlocked areas are not
allowed by default. So I am not really sure this is worth backporting to
stable trees.

> ---
>  mm/mlock.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 080f3b364..d614163f5 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -636,11 +636,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
>   * is also counted.
>   * Return value: previously mlocked page counts
>   */
> -static int count_mm_mlocked_page_nr(struct mm_struct *mm,
> +static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
>  		unsigned long start, size_t len)
>  {
>  	struct vm_area_struct *vma;
> -	int count = 0;
> +	unsigned long count = 0;
>  
>  	if (mm == NULL)
>  		mm = current->mm;
> -- 
> 2.17.1

-- 
Michal Hocko
SUSE Labs

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: [PATCH] mm: Change count_mm_mlocked_page_nr return type
  2019-04-22 10:38 Weikang shi
@ 2019-05-11  8:10 ` Souptick Joarder
  0 siblings, 0 replies; 4+ messages in thread
From: Souptick Joarder @ 2019-05-11  8:10 UTC (permalink / raw)
  To: Weikang shi; +Cc: Linux-MM, linux-kernel

On Mon, Apr 22, 2019 at 4:08 PM Weikang shi <swkhack@gmail.com> wrote:
>
> From: swkhack <swkhack@gmail.com>
>
> In 64-bit machine,the value of "vma->vm_end - vma->vm_start"
> maybe negative in 32bit int and the "count >> PAGE_SHIFT"'s rusult

s/rusult/result.

> will be wrong.So change the local variable and return
> value to unsigned long will fix the problem.
>
> Signed-off-by: swkhack <swkhack@gmail.com>
> ---
>  mm/mlock.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 080f3b364..d614163f5 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -636,11 +636,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
>   * is also counted.
>   * Return value: previously mlocked page counts
>   */
> -static int count_mm_mlocked_page_nr(struct mm_struct *mm,
> +static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
>                 unsigned long start, size_t len)
>  {
>         struct vm_area_struct *vma;
> -       int count = 0;
> +       unsigned long count = 0;
>
>         if (mm == NULL)
>                 mm = current->mm;
> --
> 2.17.1
>

^ permalink raw reply	[flat|nested] 4+ messages in thread

* [PATCH] mm: Change count_mm_mlocked_page_nr return type
@ 2019-04-22 10:38 Weikang shi
  2019-05-11  8:10 ` Souptick Joarder
  0 siblings, 1 reply; 4+ messages in thread
From: Weikang shi @ 2019-04-22 10:38 UTC (permalink / raw)
  To: linux-mm; +Cc: linux-kernel, swkhack

From: swkhack <swkhack@gmail.com>

In 64-bit machine,the value of "vma->vm_end - vma->vm_start"
maybe negative in 32bit int and the "count >> PAGE_SHIFT"'s rusult
will be wrong.So change the local variable and return
value to unsigned long will fix the problem.

Signed-off-by: swkhack <swkhack@gmail.com>
---
 mm/mlock.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/mlock.c b/mm/mlock.c
index 080f3b364..d614163f5 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -636,11 +636,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
  * is also counted.
  * Return value: previously mlocked page counts
  */
-static int count_mm_mlocked_page_nr(struct mm_struct *mm,
+static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 		unsigned long start, size_t len)
 {
 	struct vm_area_struct *vma;
-	int count = 0;
+	unsigned long count = 0;
 
 	if (mm == NULL)
 		mm = current->mm;
-- 
2.17.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2019-05-13  9:15 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-05-13  2:37 [PATCH] mm: Change count_mm_mlocked_page_nr return type Weikang shi
2019-05-13  9:15 ` Michal Hocko
  -- strict thread matches above, loose matches on Subject: below --
2019-04-22 10:38 Weikang shi
2019-05-11  8:10 ` Souptick Joarder

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