[ Upstream commit 5808b14a1f52554de612fee85ef517199855e310 ]

Fix a use-after-free bug during filesystem initialisation, where we
access the disc record (which is stored in a buffer) after we have
released the buffer.

Signed-off-by: Russell King <rmk+ker...@armlinux.org.uk>
Signed-off-by: Al Viro <v...@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 fs/adfs/super.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fs/adfs/super.c b/fs/adfs/super.c
index 7e099a7a4eb1e..4dc15b2634894 100644
--- a/fs/adfs/super.c
+++ b/fs/adfs/super.c
@@ -369,6 +369,7 @@ static int adfs_fill_super(struct super_block *sb, void 
*data, int silent)
        struct buffer_head *bh;
        struct object_info root_obj;
        unsigned char *b_data;
+       unsigned int blocksize;
        struct adfs_sb_info *asb;
        struct inode *root;
        int ret = -EINVAL;
@@ -420,8 +421,10 @@ static int adfs_fill_super(struct super_block *sb, void 
*data, int silent)
                goto error_free_bh;
        }
 
+       blocksize = 1 << dr->log2secsize;
        brelse(bh);
-       if (sb_set_blocksize(sb, 1 << dr->log2secsize)) {
+
+       if (sb_set_blocksize(sb, blocksize)) {
                bh = sb_bread(sb, ADFS_DISCRECORD / sb->s_blocksize);
                if (!bh) {
                        adfs_error(sb, "couldn't read superblock on "
-- 
2.20.1



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