linux-kernel - [PATCH v2 01/11] ext4 resise: extra brelse in setup_new_flex_group

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <37de5906-2d76-461a-ff92-b6fcc775b408@virtuozzo.com>
Date:   Wed, 31 Oct 2018 00:57:37 +0300
From:   Vasily Averin <vvs@...tuozzo.com>
To:     linux-ext4@...r.kernel.org, Theodore Ts'o <tytso@....edu>
Cc:     Andreas Dilger <adilger.kernel@...ger.ca>,
        linux-kernel@...r.kernel.org,
        Yongqiang Yang <xiaoqiangnk@...il.com>,
        Yongqiang Yang <yangyongqiang01@...du.com>
Subject: [PATCH v2 01/11] ext4 resise: extra brelse in
 setup_new_flex_group_blocks()

currently bh is set to NULL only during first iteration of for cycle,
then this pointer is not cleared after end of using.
Therefore rollback after errors can lead to extra brelse(bh) call,
decrements bh counter and later trigger an unexpected warning in __brelse()

Patch moves brelse() calls in body of cycle to exclude requirement of
brelse() call in rollback.

Fixes 33afdcc5402d ("ext4: add a function which sets up group blocks ...") # 3.3+

Signed-off-by: Vasily Averin <vvs@...tuozzo.com>
---
 fs/ext4/resize.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index ebbc663d0798..c3fa30878ca8 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -605,7 +605,6 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
-			bh = NULL;
 			goto out;
 		}
 		overhead = ext4_group_overhead_blocks(sb, group);
@@ -618,9 +617,9 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
 		ext4_mark_bitmap_end(EXT4_B2C(sbi, group_data[i].blocks_count),
 				     sb->s_blocksize * 8, bh->b_data);
 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		brelse(bh);
 		if (err)
 			goto out;
-		brelse(bh);
 
 handle_ib:
 		if (bg_flags[i] & EXT4_BG_INODE_UNINIT)
@@ -635,18 +634,16 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
 		bh = bclean(handle, sb, block);
 		if (IS_ERR(bh)) {
 			err = PTR_ERR(bh);
-			bh = NULL;
 			goto out;
 		}
 
 		ext4_mark_bitmap_end(EXT4_INODES_PER_GROUP(sb),
 				     sb->s_blocksize * 8, bh->b_data);
 		err = ext4_handle_dirty_metadata(handle, NULL, bh);
+		brelse(bh);
 		if (err)
 			goto out;
-		brelse(bh);
 	}
-	bh = NULL;
 
 	/* Mark group tables in block bitmap */
 	for (j = 0; j < GROUP_TABLE_COUNT; j++) {
@@ -685,7 +682,6 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
 	}
 
 out:
-	brelse(bh);
 	err2 = ext4_journal_stop(handle);
 	if (err2 && !err)
 		err = err2;
-- 
2.17.1