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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, Ronnie Sahlberg <lsahlber@redhat.com>,
        Jeff Layton <jlayton@kernel.org>,
        Steve French <stfrench@microsoft.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 08/18] cifs: protect updating server->dstaddr with a spinlock
Date:   Fri,  8 May 2020 14:35:11 +0200
Message-Id: <20200508123032.833331177@linuxfoundation.org>
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From: Ronnie Sahlberg <lsahlber@redhat.com>

[ Upstream commit fada37f6f62995cc449b36ebba1220594bfe55fe ]

We use a spinlock while we are reading and accessing the destination address for a server.
We need to also use this spinlock to protect when we are modifying this address from
reconn_set_ipaddr().

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/connect.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index f2707ff795d45..c018d161735c4 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -341,8 +341,10 @@ static int reconn_set_ipaddr(struct TCP_Server_Info *server)
 		return rc;
 	}
 
+	spin_lock(&cifs_tcp_ses_lock);
 	rc = cifs_convert_address((struct sockaddr *)&server->dstaddr, ipaddr,
 				  strlen(ipaddr));
+	spin_unlock(&cifs_tcp_ses_lock);
 	kfree(ipaddr);
 
 	return !rc ? -1 : 0;
-- 
2.20.1