2023-02-01 11:51:50

by Hyunmin Lee

Subject: [PATCH v4] mm/vmalloc: replace BUG_ON to a simple if statement

As per the coding standards, in the event of an abnormal condition that
should not occur under normal circumstances, the kernel should attempt
recovery and proceed with execution, rather than halting the machine.

Specifically, in the alloc_vmap_area() function, use a simple if()
instead of using BUG_ON() halting the machine.

Co-Developed-by: Gwan-gyeong Mun <[email protected]>
Co-Developed-by: Jeungwoo Yoo <[email protected]>
Co-Developed-by: Sangyun Kim <[email protected]>
Signed-off-by: Hyunmin Lee <[email protected]>
Signed-off-by: Gwan-gyeong Mun <[email protected]>
Signed-off-by: Jeungwoo Yoo <[email protected]>
Signed-off-by: Sangyun Kim <[email protected]>
Cc: Hyeonggon Yoo <[email protected]>
---
v1->v2 : Add commit description
v2->v3 : Change WARN_ON() to if()
v3->v4 : Use only one if() for three conditions
---
mm/vmalloc.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 74afa2208558..3b7e8856be35 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1587,9 +1587,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
int purged = 0;
int ret;

- BUG_ON(!size);
- BUG_ON(offset_in_page(size));
- BUG_ON(!is_power_of_2(align));
+ if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
+ return ERR_PTR(-EINVAL);

if (unlikely(!vmap_initialized))
return ERR_PTR(-EBUSY);
--
2.25.1

2023-02-01 11:59:14

by Christophe Leroy

Subject: Re: [PATCH v4] mm/vmalloc: replace BUG_ON to a simple if statement

Le 01/02/2023 à 12:51, Hyunmin Lee a écrit :
> As per the coding standards, in the event of an abnormal condition that
> should not occur under normal circumstances, the kernel should attempt
> recovery and proceed with execution, rather than halting the machine.
>
> Specifically, in the alloc_vmap_area() function, use a simple if()
> instead of using BUG_ON() halting the machine.
>
> Co-Developed-by: Gwan-gyeong Mun <[email protected]>
> Co-Developed-by: Jeungwoo Yoo <[email protected]>
> Co-Developed-by: Sangyun Kim <[email protected]>
> Signed-off-by: Hyunmin Lee <[email protected]>
> Signed-off-by: Gwan-gyeong Mun <[email protected]>
> Signed-off-by: Jeungwoo Yoo <[email protected]>
> Signed-off-by: Sangyun Kim <[email protected]>
> Cc: Hyeonggon Yoo <[email protected]>

Reviewed-by: Christophe Leroy <[email protected]>

> ---
> v1->v2 : Add commit description
> v2->v3 : Change WARN_ON() to if()
> v3->v4 : Use only one if() for three conditions
> ---
> mm/vmalloc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 74afa2208558..3b7e8856be35 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1587,9 +1587,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
> int purged = 0;
> int ret;
>
> - BUG_ON(!size);
> - BUG_ON(offset_in_page(size));
> - BUG_ON(!is_power_of_2(align));
> + if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
> + return ERR_PTR(-EINVAL);
>
> if (unlikely(!vmap_initialized))
> return ERR_PTR(-EBUSY);

2023-02-01 12:13:36

by Hyeonggon Yoo

Subject: Re: [PATCH v4] mm/vmalloc: replace BUG_ON to a simple if statement

On Wed, Feb 01, 2023 at 08:51:42PM +0900, Hyunmin Lee wrote:
> As per the coding standards, in the event of an abnormal condition that
> should not occur under normal circumstances, the kernel should attempt
> recovery and proceed with execution, rather than halting the machine.
>
> Specifically, in the alloc_vmap_area() function, use a simple if()
> instead of using BUG_ON() halting the machine.
>
> Co-Developed-by: Gwan-gyeong Mun <[email protected]>
> Co-Developed-by: Jeungwoo Yoo <[email protected]>
> Co-Developed-by: Sangyun Kim <[email protected]>
> Signed-off-by: Hyunmin Lee <[email protected]>
> Signed-off-by: Gwan-gyeong Mun <[email protected]>
> Signed-off-by: Jeungwoo Yoo <[email protected]>
> Signed-off-by: Sangyun Kim <[email protected]>
> Cc: Hyeonggon Yoo <[email protected]>
> ---
> v1->v2 : Add commit description
> v2->v3 : Change WARN_ON() to if()
> v3->v4 : Use only one if() for three conditions
> ---
> mm/vmalloc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 74afa2208558..3b7e8856be35 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1587,9 +1587,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
> int purged = 0;
> int ret;
>
> - BUG_ON(!size);
> - BUG_ON(offset_in_page(size));
> - BUG_ON(!is_power_of_2(align));
> + if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
> + return ERR_PTR(-EINVAL);
>
> if (unlikely(!vmap_initialized))
> return ERR_PTR(-EBUSY);

Reviewed-by: Hyeonggon Yoo <[email protected]>

Thanks!

> --
> 2.25.1

Regards,
Hyeonggon

2023-02-01 12:19:24

by Mike Rapoport

Subject: Re: [PATCH v4] mm/vmalloc: replace BUG_ON to a simple if statement

On Wed, Feb 01, 2023 at 08:51:42PM +0900, Hyunmin Lee wrote:
> As per the coding standards, in the event of an abnormal condition that
> should not occur under normal circumstances, the kernel should attempt
> recovery and proceed with execution, rather than halting the machine.
>
> Specifically, in the alloc_vmap_area() function, use a simple if()
> instead of using BUG_ON() halting the machine.
>
> Co-Developed-by: Gwan-gyeong Mun <[email protected]>
> Co-Developed-by: Jeungwoo Yoo <[email protected]>
> Co-Developed-by: Sangyun Kim <[email protected]>
> Signed-off-by: Hyunmin Lee <[email protected]>
> Signed-off-by: Gwan-gyeong Mun <[email protected]>
> Signed-off-by: Jeungwoo Yoo <[email protected]>
> Signed-off-by: Sangyun Kim <[email protected]>
> Cc: Hyeonggon Yoo <[email protected]>

Reviewed-by: Mike Rapoport (IBM) <[email protected]>

> ---
> v1->v2 : Add commit description
> v2->v3 : Change WARN_ON() to if()
> v3->v4 : Use only one if() for three conditions
> ---
> mm/vmalloc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 74afa2208558..3b7e8856be35 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1587,9 +1587,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
> int purged = 0;
> int ret;
>
> - BUG_ON(!size);
> - BUG_ON(offset_in_page(size));
> - BUG_ON(!is_power_of_2(align));
> + if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
> + return ERR_PTR(-EINVAL);
>
> if (unlikely(!vmap_initialized))
> return ERR_PTR(-EBUSY);
> --
> 2.25.1
>

--
Sincerely yours,
Mike.

2023-02-01 14:22:34

by Uladzislau Rezki (Sony)

Subject: Re: [PATCH v4] mm/vmalloc: replace BUG_ON to a simple if statement

On Wed, Feb 01, 2023 at 08:51:42PM +0900, Hyunmin Lee wrote:
> As per the coding standards, in the event of an abnormal condition that
> should not occur under normal circumstances, the kernel should attempt
> recovery and proceed with execution, rather than halting the machine.
>
> Specifically, in the alloc_vmap_area() function, use a simple if()
> instead of using BUG_ON() halting the machine.
>
> Co-Developed-by: Gwan-gyeong Mun <[email protected]>
> Co-Developed-by: Jeungwoo Yoo <[email protected]>
> Co-Developed-by: Sangyun Kim <[email protected]>
> Signed-off-by: Hyunmin Lee <[email protected]>
> Signed-off-by: Gwan-gyeong Mun <[email protected]>
> Signed-off-by: Jeungwoo Yoo <[email protected]>
> Signed-off-by: Sangyun Kim <[email protected]>
> Cc: Hyeonggon Yoo <[email protected]>
> ---
> v1->v2 : Add commit description
> v2->v3 : Change WARN_ON() to if()
> v3->v4 : Use only one if() for three conditions
> ---
> mm/vmalloc.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 74afa2208558..3b7e8856be35 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -1587,9 +1587,8 @@ static struct vmap_area *alloc_vmap_area(unsigned long size,
> int purged = 0;
> int ret;
>
> - BUG_ON(!size);
> - BUG_ON(offset_in_page(size));
> - BUG_ON(!is_power_of_2(align));
> + if (unlikely(!size || offset_in_page(size) || !is_power_of_2(align)))
> + return ERR_PTR(-EINVAL);
>
> if (unlikely(!vmap_initialized))
> return ERR_PTR(-EBUSY);
> --
> 2.25.1
>
Makes sense to me.

Reviewed-by: Uladzislau Rezki (Sony) <[email protected]>

--
Uladzislau Rezki