smb: client: fix deadlock in smb2_find_smb_tcon()

commit 02c418774f76a0a36a6195c9dbf8971eb4130a15 upstream.

Unlock cifs_tcp_ses_lock before calling cifs_put_smb_ses() to avoid such
deadlock.

Cc: stable@vger.kernel.org
Signed-off-by: Enzo Matsumiya <ematsumiya@suse.de>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Reviewed-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
index 8f346aafc4cf82d386c9f609b483c261cd12ef48..4ca04e62a993cf085bf9fbbc318b744be00823ca 100644 (file)
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -216,8 +216,8 @@ smb2_find_smb_tcon(struct TCP_Server_Info *server, __u64 ses_id, __u32  tid)
        }
        tcon = smb2_find_smb_sess_tcon_unlocked(ses, tid);
        if (!tcon) {
-               cifs_put_smb_ses(ses);
                spin_unlock(&cifs_tcp_ses_lock);
+               cifs_put_smb_ses(ses);
                return NULL;
        }
        spin_unlock(&cifs_tcp_ses_lock);