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From:   Ye Bin <yebin10@huawei.com>
To:     <tytso@mit.edu>, <adilger.kernel@dilger.ca>,
        <linux-ext4@vger.kernel.org>
CC:     <linux-kernel@vger.kernel.org>, <jack@suse.cz>,
        Ye Bin <yebin10@huawei.com>
Subject: [PATCH -next v2 2/3] ext4: fix potential memory leak in ext4_fc_record_regions()
Date:   Wed, 21 Sep 2022 14:40:39 +0800
Message-ID: <20220921064040.3693255-3-yebin10@huawei.com>
In-Reply-To: <20220921064040.3693255-1-yebin10@huawei.com>
References: <20220921064040.3693255-1-yebin10@huawei.com>
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Precedence: bulk

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.

Signed-off-by: Ye Bin <yebin10@huawei.com>
---
 fs/ext4/fast_commit.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 29a22ee0adb8..f5b0fc50ed47 100644
--- 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;
-- 
2.31.1