2022-09-19 14:30:38

by Ye Bin

Subject: [PATCH -next 2/2] ext4: fix potential memory leak in ext4_fc_record_modified_inode()

As krealloc may return NULL, in this case 'state->fc_modified_inodes'
may not be freed by krealloc, but 'state->fc_modified_inodes' already
set NULL. Then will lead to 'state->fc_modified_inodes' memory leak.

Signed-off-by: Ye Bin <[email protected]>
---
fs/ext4/fast_commit.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index cc8c8db075ba..5ab58cb4ce8d 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1486,13 +1486,15 @@ static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
if (state->fc_modified_inodes[i] == ino)
return 0;
if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
- state->fc_modified_inodes = krealloc(
- state->fc_modified_inodes,
+ int *fc_modified_inodes;
+
+ fc_modified_inodes = krealloc(state->fc_modified_inodes,
sizeof(int) * (state->fc_modified_inodes_size +
EXT4_FC_REPLAY_REALLOC_INCREMENT),
GFP_KERNEL);
- if (!state->fc_modified_inodes)
+ if (!fc_modified_inodes)
return -ENOMEM;
+ state->fc_modified_inodes = fc_modified_inodes;
state->fc_modified_inodes_size +=
EXT4_FC_REPLAY_REALLOC_INCREMENT;
}
--
2.31.1

2022-09-19 15:32:41

by Jan Kara

Subject: Re: [PATCH -next 2/2] ext4: fix potential memory leak in ext4_fc_record_modified_inode()

On Mon 19-09-22 22:40:21, Ye Bin wrote:
> As krealloc may return NULL, in this case 'state->fc_modified_inodes'
> may not be freed by krealloc, but 'state->fc_modified_inodes' already
> set NULL. Then will lead to 'state->fc_modified_inodes' memory leak.
>
> Signed-off-by: Ye Bin <[email protected]>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <[email protected]>

Honza

> ---
> fs/ext4/fast_commit.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
> index cc8c8db075ba..5ab58cb4ce8d 100644
> --- a/fs/ext4/fast_commit.c
> +++ b/fs/ext4/fast_commit.c
> @@ -1486,13 +1486,15 @@ static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
> if (state->fc_modified_inodes[i] == ino)
> return 0;
> if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
> - state->fc_modified_inodes = krealloc(
> - state->fc_modified_inodes,
> + int *fc_modified_inodes;
> +
> + fc_modified_inodes = krealloc(state->fc_modified_inodes,
> sizeof(int) * (state->fc_modified_inodes_size +
> EXT4_FC_REPLAY_REALLOC_INCREMENT),
> GFP_KERNEL);
> - if (!state->fc_modified_inodes)
> + if (!fc_modified_inodes)
> return -ENOMEM;
> + state->fc_modified_inodes = fc_modified_inodes;
> state->fc_modified_inodes_size +=
> EXT4_FC_REPLAY_REALLOC_INCREMENT;
> }
> --
> 2.31.1
>
--
Jan Kara <[email protected]>
SUSE Labs, CR