[PATCH 5.15 102/530] ext4: fix potential memory leak in ext4_fc_record_regions()

[Greg Kroah-Hartman]

From: Ye Bin <yebin10@xxxxxxxxxx>

commit 7069d105c1f15c442b68af43f7fde784f3126739 upstream.

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@xxxxxxxxxx
Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Link: https://lore.kernel.org/r/20220921064040.3693255-3-yebin10@xxxxxxxxxx
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/ext4/fast_commit.c |   14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1607,15 +1607,17 @@ int ext4_fc_record_regions(struct super_
 	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;