[PATCH] quota: Check for register_shrinker() failure.

[PATCH] quota: Check for register_shrinker() failure.

[Tetsuo Handa]

register_shrinker() might return -ENOMEM error since Linux 3.12.
Call panic() as with other failure checks in this function if
register_shrinker() failed.

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Jan Kara <jack@suse.com>
Cc: Michal Hocko <mhocko@suse.com>
---
 fs/quota/dquot.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 39f1b0b..1429f03 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2985,7 +2985,8 @@ static int __init dquot_init(void)
 	pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
 		" %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
 
-	register_shrinker(&dqcache_shrinker);
+	if (register_shrinker(&dqcache_shrinker))
+		panic("Cannot register dquot shrinker");
 
 	return 0;
 }
-- 
1.8.3.1

Re: [PATCH] quota: Check for register_shrinker() failure.

[Michal Hocko]

On Wed 29-11-17 22:34:50, Tetsuo Handa wrote:
> register_shrinker() might return -ENOMEM error since Linux 3.12.
> Call panic() as with other failure checks in this function if
> register_shrinker() failed.
> 
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>

Fixes: 1d3d4437eae1 ("vmscan: per-node deferred work")

> Cc: Jan Kara <jack@suse.com>
> Cc: Michal Hocko <mhocko@suse.com>

>From my very limited understanding of the code this looks correct.
FWIW
Reviewed-by: Michal Hocko <mhocko@suse.com>

> ---
>  fs/quota/dquot.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
> index 39f1b0b..1429f03 100644
> --- a/fs/quota/dquot.c
> +++ b/fs/quota/dquot.c
> @@ -2985,7 +2985,8 @@ static int __init dquot_init(void)
>  	pr_info("VFS: Dquot-cache hash table entries: %ld (order %ld,"
>  		" %ld bytes)\n", nr_hash, order, (PAGE_SIZE << order));
>  
> -	register_shrinker(&dqcache_shrinker);
> +	if (register_shrinker(&dqcache_shrinker))
> +		panic("Cannot register dquot shrinker");
>  
>  	return 0;
>  }
> -- 
> 1.8.3.1
> 

-- 
Michal Hocko
SUSE Labs

Re: [PATCH] quota: Check for register_shrinker() failure.

[Jan Kara]

On Wed 29-11-17 14:42:51, Michal Hocko wrote:
> On Wed 29-11-17 22:34:50, Tetsuo Handa wrote:
> > register_shrinker() might return -ENOMEM error since Linux 3.12.
> > Call panic() as with other failure checks in this function if
> > register_shrinker() failed.
> > 
> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> 
> Fixes: 1d3d4437eae1 ("vmscan: per-node deferred work")
> 
> > Cc: Jan Kara <jack@suse.com>
> > Cc: Michal Hocko <mhocko@suse.com>
> 
> From my very limited understanding of the code this looks correct.
> FWIW
> Reviewed-by: Michal Hocko <mhocko@suse.com>

Thanks. Added to my tree.

								Honza
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR