2014-10-31 10:14:21

by Li Haifeng

Subject: [PATCH] Frontswap: fix the condition in BUG_ON

>From 012a564c7210346b99d12e3d2485542bb090586e Mon Sep 17 00:00:00 2001
From: Haifeng Li <[email protected]>
Date: Fri, 31 Oct 2014 17:40:44 +0800
Subject: [PATCH] Frontswap: fix the condition in BUG_ON

The largest index of swap device is MAX_SWAPFILES-1. So the type
should be less than MAX_SWAPFILES.

Signed-off-by: Haifeng Li <[email protected]>
---
mm/frontswap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/frontswap.c b/mm/frontswap.c
index c30eec5..1b80c05 100644
--- a/mm/frontswap.c
+++ b/mm/frontswap.c
@@ -182,7 +182,7 @@ void __frontswap_init(unsigned type, unsigned long *map)
if (frontswap_ops)
frontswap_ops->init(type);
else {
- BUG_ON(type > MAX_SWAPFILES);
+ BUG_ON(type >= MAX_SWAPFILES);
set_bit(type, need_init);
}
}
--
1.9.1

2014-10-31 14:10:22

by Konrad Rzeszutek Wilk

Subject: Re: [PATCH] Frontswap: fix the condition in BUG_ON

On Fri, Oct 31, 2014 at 06:14:19PM +0800, Li Haifeng wrote:
> >From 012a564c7210346b99d12e3d2485542bb090586e Mon Sep 17 00:00:00 2001
> From: Haifeng Li <[email protected]>
> Date: Fri, 31 Oct 2014 17:40:44 +0800
> Subject: [PATCH] Frontswap: fix the condition in BUG_ON
>
> The largest index of swap device is MAX_SWAPFILES-1. So the type
> should be less than MAX_SWAPFILES.

Ok, so we would never hit this BUG_ON because of that.

Acked-by: Konrad Rzeszutek Wilk <[email protected]>

P.S.
Andrew - are you OK picking this up?

Thank you!
>
> Signed-off-by: Haifeng Li <[email protected]>
> ---
> mm/frontswap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/frontswap.c b/mm/frontswap.c
> index c30eec5..1b80c05 100644
> --- a/mm/frontswap.c
> +++ b/mm/frontswap.c
> @@ -182,7 +182,7 @@ void __frontswap_init(unsigned type, unsigned long *map)
> if (frontswap_ops)
> frontswap_ops->init(type);
> else {
> - BUG_ON(type > MAX_SWAPFILES);
> + BUG_ON(type >= MAX_SWAPFILES);
> set_bit(type, need_init);
> }
> }
> --
> 1.9.1