ext4: fix potential memory leak in ext4_fc_record_regions()

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

Cc: stable@kernel.org
Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220921064040.3693255-3-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 9555ab8..5ab58cb 100644 (file)
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1679,15 +1679,17 @@ int ext4_fc_record_regions(struct super_block *sb, int ino,
        if (replay && state->fc_regions_used != state->fc_regions_valid)
                state->fc_regions_used = state->fc_regions_valid;
        if (state->fc_regions_used == state->fc_regions_size) {
+               struct ext4_fc_alloc_region *fc_regions;
+
                state->fc_regions_size +=
                        EXT4_FC_REPLAY_REALLOC_INCREMENT;
-               state->fc_regions = krealloc(
-                                       state->fc_regions,
-                                       state->fc_regions_size *
-                                       sizeof(struct ext4_fc_alloc_region),
-                                       GFP_KERNEL);
-               if (!state->fc_regions)
+               fc_regions = krealloc(state->fc_regions,
+                                     state->fc_regions_size *
+                                     sizeof(struct ext4_fc_alloc_region),
+                                     GFP_KERNEL);
+               if (!fc_regions)
                        return -ENOMEM;
+               state->fc_regions = fc_regions;
        }
        region = &state->fc_regions[state->fc_regions_used++];
        region->ino = ino;