From mboxrd@z Thu Jan 1 00:00:00 1970 From: linux@armlinux.org.uk (Russell King - ARM Linux) Date: Thu, 10 May 2018 20:44:22 +0100 Subject: [PATCH 2/4] pid: Export find_task_by_vpid for use in external modules In-Reply-To: References: <20180508140640.0e312dba025df75cbf205cdb@arm.com> <87d0y5toed.fsf@xmission.com> <20180509152505.GA25559@xps15> <87k1scs0f8.fsf@xmission.com> <20180510084057.GT16141@n2100.armlinux.org.uk> Message-ID: <20180510194422.GX16141@n2100.armlinux.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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? -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up