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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, David Howells <dhowells@redhat.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        linux-s390@vger.kernel.org, Al Viro <viro@zeniv.linux.org.uk>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.2 120/137] hypfs: Fix error number left in struct pointer member
Date:   Sun,  6 Oct 2019 19:21:44 +0200
Message-Id: <20191006171219.261730265@linuxfoundation.org>
In-Reply-To: <20191006171209.403038733@linuxfoundation.org>
References: <20191006171209.403038733@linuxfoundation.org>
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From: David Howells <dhowells@redhat.com>

[ Upstream commit b54c64f7adeb241423cd46598f458b5486b0375e ]

In hypfs_fill_super(), if hypfs_create_update_file() fails,
sbi->update_file is left holding an error number.  This is passed to
hypfs_kill_super() which doesn't check for this.

Fix this by not setting sbi->update_value until after we've checked for
error.

Fixes: 24bbb1faf3f0 ("[PATCH] s390_hypfs filesystem")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
cc: Heiko Carstens <heiko.carstens@de.ibm.com>
cc: linux-s390@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/s390/hypfs/inode.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/s390/hypfs/inode.c b/arch/s390/hypfs/inode.c
index ccad1398abd40..b5cfcad953c2e 100644
--- a/arch/s390/hypfs/inode.c
+++ b/arch/s390/hypfs/inode.c
@@ -269,7 +269,7 @@ static int hypfs_show_options(struct seq_file *s, struct dentry *root)
 static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 {
 	struct inode *root_inode;
-	struct dentry *root_dentry;
+	struct dentry *root_dentry, *update_file;
 	int rc = 0;
 	struct hypfs_sb_info *sbi;
 
@@ -300,9 +300,10 @@ static int hypfs_fill_super(struct super_block *sb, void *data, int silent)
 		rc = hypfs_diag_create_files(root_dentry);
 	if (rc)
 		return rc;
-	sbi->update_file = hypfs_create_update_file(root_dentry);
-	if (IS_ERR(sbi->update_file))
-		return PTR_ERR(sbi->update_file);
+	update_file = hypfs_create_update_file(root_dentry);
+	if (IS_ERR(update_file))
+		return PTR_ERR(update_file);
+	sbi->update_file = update_file;
 	hypfs_update_update(sb);
 	pr_info("Hypervisor filesystem mounted\n");
 	return 0;
-- 
2.20.1