From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZpEIbO+Cu9plltMGZmV7faDpVcJCRFTk0k07BYkb+VJp0PD0e6sDCfYBJc6Sa2UugCS1ubx ARC-Seal: i=1; a=rsa-sha256; t=1526535588; cv=none; d=google.com; s=arc-20160816; b=eEzh+RqghNNl6XQ6fh49dwxGpaoMWwTEGBAEzUXfLQai/3bNI0cfcXlJlKIaOIMqpT m4VBeQagwCratlNGY4P0G+dMs9pbdrWDM3jd7xpIApYZVycQ14D7TZed/mD83UhYbf3B 1nCuyU1AVXrdD7YoMyRehQXY/oB7CIi5zCABB5NL4f3bjrIWQca61OqzC1gSy4FdgG38 3CQ7Yw4ojMfvFm0k4vIT4r/VAOnOI+xwGifDMCCQkwR0ouUT2U8meM53hINsvGkT10Rp PVIs3L3B9M2vI+HIjgyHj+yOTsSPpy8vqm0uYeNGCMtYcIKtXyAR0gWxuz0s2iqARSks fu2Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=subject:mime-version:user-agent:message-id:in-reply-to:date :references:cc:to:from:arc-authentication-results; bh=1sIoPmuRy6aK7offSX5VcEixv/vn5ebBpCYqxJaYyMA=; b=ijMvZ0YJrc6kljy1vZCVVJMMELbSUYADcQEi3j/s5hVZSBriwt/OxneOV9RpzQem4U tP6scge0F+f4MOgj/LNGXL6zMLWw6KwYzwk4Jr1+yDNsXwNvBBarXGsLLvtt7aZQFTr8 XJf64a11KoP9A7pJlPVjGrktn2ErwoaZT7OghbiMRCv8CDeS9KCiYOX3JCwDk4H94XGs n+gWLNyRlrpyfDEcJC6SCPfF/Ja6E8gL2LFxjXVbQ0sLuOpYZhQrXSsiPdrQ54H3exaO 9FAHxfryFs8q8o66Z7oi9eEr9JN110My7X3AX4qz2mKDZKw/RKfFpoYyW9StM7wmYWxK k/IA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of ebiederm@xmission.com designates 166.70.13.231 as permitted sender) smtp.mailfrom=ebiederm@xmission.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of ebiederm@xmission.com designates 166.70.13.231 as permitted sender) smtp.mailfrom=ebiederm@xmission.com From: ebiederm@xmission.com (Eric W. Biederman) To: Russell King - ARM Linux Cc: Mathieu Poirier , Kim Phillips , Alexander Shishkin , Alex Williamson , Andrew Morton , David Howells , Eric Auger , Gargi Sharma , Geert Uytterhoeven , Greg Kroah-Hartman , Kefeng Wang , Kirill Tkhai , Mike Rapoport , Oleg Nesterov , Pavel Tatashin , Rik van Riel , Robin Murphy , Thierry Reding , Todd Kjos , linux-arm-kernel , linux-kernel@vger.kernel.org References: <20180508140640.0e312dba025df75cbf205cdb@arm.com> <87d0y5toed.fsf@xmission.com> <20180509152505.GA25559@xps15> <87k1scs0f8.fsf@xmission.com> <20180510084057.GT16141@n2100.armlinux.org.uk> <20180510194422.GX16141@n2100.armlinux.org.uk> Date: Thu, 17 May 2018 00:39:37 -0500 In-Reply-To: <20180510194422.GX16141@n2100.armlinux.org.uk> (Russell King's message of "Thu, 10 May 2018 20:44:22 +0100") Message-ID: <87k1s2j0x2.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1fJBdf-0004lw-QH;;;mid=<87k1s2j0x2.fsf@xmission.com>;;;hst=in01.mta.xmission.com;;;ip=97.90.247.198;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18imAWKBCkq3kVz8yIHNpLev3T+O5HQgSI= X-SA-Exim-Connect-IP: 97.90.247.198 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.5 XMGappySubj_01 Very gappy subject * 0.7 XMSubLong Long Subject * 1.5 XMNoVowels Alpha-numberic number with no vowels * 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: 0.4992] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: **;Russell King - ARM Linux X-Spam-Relay-Country: X-Spam-Timing: total 1060 ms - load_scoreonly_sql: 0.04 (0.0%), signal_user_changed: 3.3 (0.3%), b_tie_ro: 2.2 (0.2%), parse: 1.01 (0.1%), extract_message_metadata: 11 (1.0%), get_uri_detail_list: 1.41 (0.1%), tests_pri_-1000: 6 (0.6%), tests_pri_-950: 1.15 (0.1%), tests_pri_-900: 0.99 (0.1%), tests_pri_-400: 22 (2.1%), check_bayes: 21 (2.0%), b_tokenize: 7 (0.7%), b_tok_get_all: 7 (0.6%), b_comp_prob: 2.0 (0.2%), b_tok_touch_all: 3.6 (0.3%), b_finish: 0.64 (0.1%), tests_pri_0: 142 (13.4%), check_dkim_signature: 0.46 (0.0%), check_dkim_adsp: 2.5 (0.2%), tests_pri_500: 869 (82.0%), poll_dns_idle: 864 (81.5%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH 2/4] pid: Export find_task_by_vpid for use in external modules X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1599923977519130436?= X-GMAIL-MSGID: =?utf-8?q?1600688581622839426?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Russell King - ARM Linux writes: > On Thu, May 10, 2018 at 01:39:18PM -0600, Mathieu Poirier wrote: >> Hi Russell, >> >> On 10 May 2018 at 02:40, Russell King - ARM Linux wrote: >> > This does not leak information from other namespaces because of the >> > uniqueness of the global PID. However, what it does leak is the value >> > of the global PID which is meaningless in the namespace. So, before >> > the event stream is delivered to userspace, this value needs to be >> > re-written to the namespace's PID value. >> >> Unfortunately that can't be done. The trace stream is compressed and >> needs to be decompressed using an external library. I think the only >> option is to return an error if a user is trying to use this feature >> from a namespace. > > That sounds like a sensible approach, and that should get rid of the > vpid stuff too. > > Eric, would this solve all your concerns? It does, and I have given my ack to the respin. I am moderately concerned about using the global pid with hardware. But pids are a core abstraction that aren't going anywhere. As long as hardware does not impose constraints on pids that software already does not we should be fine. Eric