From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out01.mta.xmission.com (out01.mta.xmission.com [166.70.13.231]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC1CF70 for ; Tue, 29 Jun 2021 17:09:43 +0000 (UTC) Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lyHF0-008vqB-Mu; Tue, 29 Jun 2021 11:09:42 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95]:60780 helo=email.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1lyHEy-0020Vr-Mu; Tue, 29 Jun 2021 11:09:42 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Linus Torvalds Cc: Alexey Gladkov , Linux Kernel Mailing List , Linux Containers References: <87fsx1vcr9.fsf@disp2133> <87czs4u0rm.fsf@disp2133> <87mtr8sjvr.fsf@disp2133> Date: Tue, 29 Jun 2021 12:09:01 -0500 In-Reply-To: <87mtr8sjvr.fsf@disp2133> (Eric W. Biederman's message of "Tue, 29 Jun 2021 11:42:00 -0500") Message-ID: <87a6n8simq.fsf@disp2133> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) Precedence: bulk X-Mailing-List: containers@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1lyHEy-0020Vr-Mu;;;mid=<87a6n8simq.fsf@disp2133>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18eZPW1C7TY8UVdKymDCO/XEtzG8z7YA2M= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa06.xmission.com X-Spam-Level: ** X-Spam-Status: No, score=2.8 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TM2_M_HEADER_IN_MSG,XMSubLong,XMSubMetaSxObfu_03, XMSubMetaSx_00 autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4446] * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 1.2 XMSubMetaSxObfu_03 Obfuscated Sexy Noun-People * 1.0 XMSubMetaSx_00 1+ Sexy Words X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **;Linus Torvalds X-Spam-Relay-Country: X-Spam-Timing: total 1448 ms - load_scoreonly_sql: 0.05 (0.0%), signal_user_changed: 10 (0.7%), b_tie_ro: 9 (0.6%), parse: 1.54 (0.1%), extract_message_metadata: 24 (1.6%), get_uri_detail_list: 2.1 (0.1%), tests_pri_-1000: 41 (2.8%), tests_pri_-950: 1.66 (0.1%), tests_pri_-900: 1.27 (0.1%), tests_pri_-90: 94 (6.5%), check_bayes: 92 (6.3%), b_tokenize: 8 (0.6%), b_tok_get_all: 6 (0.4%), b_comp_prob: 2.4 (0.2%), b_tok_touch_all: 72 (4.9%), b_finish: 0.95 (0.1%), tests_pri_0: 1256 (86.8%), check_dkim_signature: 0.68 (0.0%), check_dkim_adsp: 3.1 (0.2%), poll_dns_idle: 0.86 (0.1%), tests_pri_10: 3.2 (0.2%), tests_pri_500: 11 (0.7%), rewrite_mail: 0.00 (0.0%) Subject: Re: [GIT PULL] ucounts: Count rlimits in each user namespace X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) ebiederm@xmission.com (Eric W. Biederman) writes: > Linus Torvalds writes: > >> On Tue, Jun 29, 2021 at 8:52 AM Eric W. Biederman wrote: >>> >>> Linus Torvalds writes: >>> >>> > Why the "sigpending < LONG_MAX" test in that >>> > >>> > if (override_rlimit || (sigpending < LONG_MAX && sigpending <= >>> > task_rlimit(t, RLIMIT_SIGPENDING))) { >>> > thing? >>> >>> On second look that sigpending < LONG_MAX check is necessary. When >>> inc_rlimit_ucounts detects a problem it returns LONG_MAX. >> >> I saw that, but _without_ that test you'd be left with just that >> >> sigpending <= task_rlimit(t, RLIMIT_SIGPENDING) >> >> and if task_rlimit() is LONG_MAX, then that means "no limits", so it is all ok. > > It means no limits locally. The creator of your user namespace might > have had a limit which you are also bound by. > > The other possibility is that inc_rlimits_ucounts caused a sigpending > counter to overflow. In which case we need to fail and run > dec_rlimit_ucounts to keep the counter from staying overflowed. > > So I don't see a clever way to avoid the sigpending < LONG_MAX test. Hmm. I take that back. There is a simple clever way to satisfy all of the tests. - sigpending < LONG_MAX && sigpending <= task_rlimit(t, RLIMIT_SIGPENDING) + sigpending < task_rlimit(t, RLIMIT_SIGPENDING) That would just need a small comment to explain the subtleties. Eric