Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752373AbaLITeK (ORCPT ); Tue, 9 Dec 2014 14:34:10 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:40439 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751047AbaLITeD (ORCPT ); Tue, 9 Dec 2014 14:34:03 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Andy Lutomirski Cc: Linux Containers , Josh Triplett , Andrew Morton , Kees Cook , Michael Kerrisk-manpages , Linux API , linux-man , "linux-kernel\@vger.kernel.org" , LSM , Casey Schaufler , "Serge E. Hallyn" , Richard Weinberger , Kenton Varda , stable References: <52e0643bd47b1e5c65921d6e00aea1f724bb510a.1417281801.git.luto@amacapital.net> <87h9xez20g.fsf@x220.int.ebiederm.org> <87mw75ygwp.fsf@x220.int.ebiederm.org> <87fvcxyf28.fsf_-_@x220.int.ebiederm.org> <874mtdyexp.fsf_-_@x220.int.ebiederm.org> <87a935u3nj.fsf@x220.int.ebiederm.org> <87388xodlj.fsf@x220.int.ebiederm.org> <87h9x5re41.fsf_-_@x220.int.ebiederm.org> <87mw6xpzb0.fsf_-_@x220.int.ebiederm.org> <87ppbtn4mv.fsf@x220.int.ebiederm.org> <87a92xn2io.fsf@x220.int.ebiederm.org> Date: Tue, 09 Dec 2014 13:31:39 -0600 In-Reply-To: <87a92xn2io.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Mon, 08 Dec 2014 17:30:07 -0600") Message-ID: <87r3w8liw4.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1/jvGGNXLbu1QONlcnp7BVCRwllCtBa+Gg= X-SA-Exim-Connect-IP: 67.3.210.55 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 TVD_RCVD_IP Message was received from an IP address * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.7 XMSubLong Long Subject * 1.5 TR_Symld_Words too many words that have symbols inside * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] * 1.0 XMSubMetaSx_00 1+ Sexy Words * 1.2 XMSubMetaSSx_00 1+ SortaSexy Words + 1 Sexy Word X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: *****;Andy Lutomirski X-Spam-Relay-Country: X-Spam-Timing: total 597 ms - load_scoreonly_sql: 0.05 (0.0%), signal_user_changed: 5 (0.9%), b_tie_ro: 4.2 (0.7%), parse: 0.70 (0.1%), extract_message_metadata: 13 (2.2%), get_uri_detail_list: 0.87 (0.1%), tests_pri_-1000: 8 (1.4%), tests_pri_-950: 1.20 (0.2%), tests_pri_-900: 1.08 (0.2%), tests_pri_-400: 18 (3.1%), check_bayes: 17 (2.9%), b_tokenize: 5 (0.9%), b_tok_get_all: 6 (1.0%), b_comp_prob: 1.54 (0.3%), b_tok_touch_all: 2.1 (0.4%), b_finish: 0.70 (0.1%), tests_pri_0: 542 (90.8%), tests_pri_500: 4.8 (0.8%), rewrite_mail: 0.00 (0.0%) Subject: Re: [CFT][PATCH 6/7] userns: Add a knob to disable setgroups on a per user namespace basis X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 24 Sep 2014 11:00:52 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ebiederm@xmission.com (Eric W. Biederman) writes: > Andy Lutomirski writes: > >> >> This text was actually my suggested comment text. > > Now I see. > >> If you put smp_rmb() in this function with a comment like that, then I >> think it will all make sense and be obviously correct (even with most >> of the other barriers removed). > > Right. > > Given that we have to be careful when using these things anyway what > I was hoping to achieve with the barriers appears impossible, and > confusing so I will see about just adding barriers where we need them > for real. Sigh. Doh. The code has been entirely too clever. There are no need for atomics or other cleverness, I just need to generalize id_map_mutex. I knew that had to be a trivially correct way of handling this mess. Eric -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/