smb: client: fix deadlock in smb2_find_smb_tcon()

[ Upstream commit 02c4187 ]

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: Sasha Levin <sashal@kernel.org>

fs/cifs/smb2transport.c

@@ -207,8 +207,8 @@ 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);