Comment # 3 on bug 1195360 from Jiri Slaby

>  cifs_get_smb_ses+0x674/0xdc0 [cifs 7ef9028630b6a8ae2a075c5cad1bded3495fffbf]

Oh, there is:
        if (ctx->workstation_name) {
                ses->workstation_name = kstrdup(ctx->workstation_name,
                                                GFP_KERNEL);
                if (!ses->workstation_name)
                        goto get_ses_fail;
        }

So apparently the context has workstation_name == NULL and the dup didn't
happen. So there should be a check of workstation_name in size_of_ntlmssp_blob.