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From: Chunguang Xu <brookxu.cn@gmail.com>
To: tytso@mit.edu, adilger.kernel@dilger.ca
Cc: linux-ext4@vger.kernel.org
Subject: [PATCH 8/8] ext4: fix a memory leak of ext4_free_data
Date: Wed, 21 Oct 2020 17:15:28 +0800	[thread overview]
Message-ID: <1603271728-7198-8-git-send-email-brookxu@tencent.com> (raw)
In-Reply-To: <1603271728-7198-1-git-send-email-brookxu@tencent.com>

From: Chunguang Xu <brookxu@tencent.com>

When freeing metadata, we will create an ext4_free_data and
insert it into the pending free list. After the current
transaction is committed, the object will be freed.

ext4_mb_free_metadata() will check whether the area to be
freed overlaps with the pending free list. If true, return
directly. At this time, ext4_free_data is leaked. Fortunately,
the probability of this problem is relatively small, maybe we
should fix this problem.

Signed-off-by: Chunguang Xu <brookxu@tencent.com>
---
 fs/ext4/mballoc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 2b1bc6c..3af4903 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -5146,6 +5146,7 @@ int ext4_metadata_block_overlaps(struct super_block *sb,
 				ext4_group_first_block_no(sb, group) +
 				EXT4_C2B(sbi, cluster),
 				"Block already on to-be-freed list");
+			kmem_cache_free(ext4_free_data_cachep, new_entry);
 			return 0;
 		}
 	}
-- 
1.8.3.1


      parent reply	other threads:[~2020-10-21  9:16 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-21  9:15 [PATCH 1/8] ext4: use ext4_assert() to replace J_ASSERT() Chunguang Xu
2020-10-21  9:15 ` [PATCH 2/8] ext4: remove redundant mb_regenerate_buddy() Chunguang Xu
2020-10-23 22:58   ` Andreas Dilger
2020-10-21  9:15 ` [PATCH 3/8] ext4: simplify the code of mb_find_order_for_block Chunguang Xu
2020-10-23 23:07   ` Andreas Dilger
2020-10-21  9:15 ` [PATCH 4/8] ext4: add the gdt block of meta_bg to system_zone Chunguang Xu
2020-10-21  9:15 ` [PATCH 5/8] ext4: update ext4_data_block_valid related comments Chunguang Xu
2020-10-23 23:09   ` Andreas Dilger
2020-10-21  9:15 ` [PATCH 6/8] ext4: add a helper function to validate metadata block Chunguang Xu
2020-10-21  9:15 ` [PATCH 7/8] ext4: delete invalid code inside ext4_xattr_block_set() Chunguang Xu
2020-10-23 23:10   ` Andreas Dilger
2020-10-21  9:15 ` Chunguang Xu [this message]

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