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| author | Tao Ma <boyu.mt@taobao.com> | 2011-07-12 02:42:42 +0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2011-07-12 02:42:42 +0400 |
| commit | caaf7a29d31da21bb8d8200d5e42d1c93d3c6e00 (patch) | |
| tree | 880f1cd67f0a8c1fb1dfbb1359358d930b0f611a /fs/ext4/mballoc.c | |
| parent | 823ba01fc07751200c43e45733925a98b73eac3a (diff) | |
| download | linux-caaf7a29d31da21bb8d8200d5e42d1c93d3c6e00.tar.xz | |
ext4: Fix a double free of sbi->s_group_info in ext4_mb_init_backend
If we meet with an error in ext4_mb_add_groupinfo, we kfree
sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)], but fail to
reset it to NULL. So the caller ext4_mb_init_backend will try to kfree
it again and causes a double free. So fix it by resetting it to NULL.
Some typo in comments of mballoc.c are also changed.
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/mballoc.c')
| -rw-r--r-- | fs/ext4/mballoc.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 2b9a71b99b2b..b97a2d2f0fdf 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -75,8 +75,8 @@ * * The inode preallocation space is used looking at the _logical_ start * block. If only the logical file block falls within the range of prealloc - * space we will consume the particular prealloc space. This make sure that - * that the we have contiguous physical blocks representing the file blocks + * space we will consume the particular prealloc space. This makes sure that + * we have contiguous physical blocks representing the file blocks * * The important thing to be noted in case of inode prealloc space is that * we don't modify the values associated to inode prealloc space except @@ -84,7 +84,7 @@ * * If we are not able to find blocks in the inode prealloc space and if we * have the group allocation flag set then we look at the locality group - * prealloc space. These are per CPU prealloc list repreasented as + * prealloc space. These are per CPU prealloc list represented as * * ext4_sb_info.s_locality_groups[smp_processor_id()] * @@ -152,7 +152,7 @@ * best extent in the found extents. Searching for the blocks starts with * the group specified as the goal value in allocation context via * ac_g_ex. Each group is first checked based on the criteria whether it - * can used for allocation. ext4_mb_good_group explains how the groups are + * can be used for allocation. ext4_mb_good_group explains how the groups are * checked. * * Both the prealloc space are getting populated as above. So for the first @@ -2279,8 +2279,10 @@ int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group, exit_group_info: /* If a meta_group_info table has been allocated, release it now */ - if (group % EXT4_DESC_PER_BLOCK(sb) == 0) + if (group % EXT4_DESC_PER_BLOCK(sb) == 0) { kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]); + sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] = NULL; + } exit_meta_group_info: return -ENOMEM; } /* ext4_mb_add_groupinfo */ |