Re: [PATCH] ext4: memory leakage in ext4_mb_init()

["Aneesh Kumar K. V" <aneesh.kumar@linux.vnet.ibm.com>]

On Sun, 21 Mar 2010 22:01:06 +0800, jing zhang <zj.barak@gmail.com> wrote:
> From: Jing Zhang <zj.barak@gmail.com>
> 
> Date: Sun Mar 21 21:59:35     2010
> 
> Cc: Theodore Ts'o <tytso@mit.edu>
> Cc: Andreas Dilger <adilger@sun.com>
> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com>
> Signed-off-by: Jing Zhang <zj.barak@gmail.com>
> 
> ---
> 
> --- linux-2.6.32/fs/ext4/mballoc.c	2009-12-03 11:51:22.000000000 +0800
> +++ ext4_mm_leak/mballoc3.c	2010-03-21 21:37:18.000000000 +0800
> @@ -2360,6 +2360,24 @@ err_freesgi:
>  	return -ENOMEM;
>  }
> 
> +static void ext4_mb_destroy_backend(struct super_block *sb)
> +{
> +	ext4_group_t ngroups = ext4_get_groups_count(sb);
> +	ext4_group_t i;
> +	struct ext4_sb_info *sbi = EXT4_SB(sb);
> +	int j;
> +	int num_meta_group_infos = (ngroups + EXT4_DESC_PER_BLOCK(sb) -1)
> +					>> EXT4_DESC_PER_BLOCK_BITS(sb);
> +	for (i = 0; i < ngroups; i++)
> +		kfree(ext4_get_group_info(sb, i));
> +
> +	for (j = 0; j < num_meta_group_infos; j++)
> +		kfree(sbi->s_group_info[j]);
> +
> +	kfree(sbi->s_group_info);
> +	iput(sbi->s_buddy_cache);
> +}
> +
>  int ext4_mb_init(struct super_block *sb, int needs_recovery)
>  {
>  	struct ext4_sb_info *sbi = EXT4_SB(sb);
> @@ -2419,6 +2437,7 @@ int ext4_mb_init(struct super_block *sb,
>  	if (sbi->s_locality_groups == NULL) {
>  		kfree(sbi->s_mb_offsets);
>  		kfree(sbi->s_mb_maxs);
> +		ext4_mb_destroy_backend(sb);
>  		return -ENOMEM;
>  	}
>  	for_each_possible_cpu(i) {

A better fix would be move s_locality_group allocation before
ext4_mb_init_backend

-aneesh