[lttng-dev] Debian specific userspace RCU configure override

[Mathieu Desnoyers]

----- Original Message -----
> From: "Daniel Thibault" <Daniel.Thibault at drdc-rddc.gc.ca>
> To: lttng-dev at lists.lttng.org
> Cc: "Jon Bernard" <jbernard at debian.org>, "Mathieu Desnoyers" <mathieu.desnoyers at efficios.com>, "Ondřej Surý"
> <ondrej at sury.org>, "Michael Jeanson" <mjeanson at efficios.com>
> Sent: Thursday, June 5, 2014 1:49:43 PM
> Subject: Re: [lttng-dev] Debian specific userspace RCU configure override
> 
> ----------------------------------------------------------------------
> Date: Wed, 28 May 2014 14:10:50 -0400
> 
> > As I currently understand, the debian build problem is that although the
> > package is compiled on armv7 hardware, it is expected to target armv4t.
> > And this is not correctly detected at configure-time.  The folks on
> > #debian-arm suggested that this could be solved in configure.ac.  I can
> > explicitly pass '--build <target>' to ./configure to get around this,
> > but arm users that build from source will need to remember this.
> >
> > Jon
> ----------------------------------------------------------------------
>    I need to revive this thread.  Although the original build failure may
>    have been on ARMv7 wanting ARMv4, I've run into the same failure with a
>    pure ARMv7 architecture.  Specifically, Beagle Bone Black.
> 
>    I built userspace-rcu without trouble (except for that clock business
>    reported earlier), but when I then tried to build lttng-ust, I ran into
>    the same 'Error: selected processor does not support ARM mode `dmb'.
>    Taking a look at the userspace-rcu and lttng-ust config.logs, they
>    *both* report 'uname -m = armv7l'.  The core tests *both* report a build
>    system type of 'armv7l-unknown-linux-gnueabi'.  However, userspace-rcu
>    tests for dmb and finds it, while lttng-ust omits this test.
> 
>    The make error occurs during the CCLD of libringbuffer.la.
> 
>    Besides the make, config and configure logs, what should I post here?

You probably built lttng-ust against a mismatching version of urcu headers.

Make sure you issue "make clean" in your lttng-ust tree, double-check that
the urcu/config.h header installed in your system (the one used by the
lttng-ust build) has the CONFIG_RCU_ARM_HAVE_DMB define in the correct state
(the one detected by urcu configure).

Thanks,

Mathieu

> 
> Daniel U. Thibault
> Protection des systèmes et contremesures (PSC) | Systems Protection &
> Countermeasures (SPC)
> Cyber sécurité pour les missions essentielles (CME) | Mission Critical Cyber
> Security (MCCS)
> RDDC - Centre de recherches de Valcartier | DRDC - Valcartier Research Centre
> 2459 route de la Bravoure
> Québec QC  G3J 1X5
> CANADA
> Vox : (418) 844-4000 x4245
> Fax : (418) 844-4538
> NAC : 918V QSDJ <http://www.travelgis.com/map.asp?addr=918V%20QSDJ>
> Gouvernement du Canada | Government of Canada
> <http://www.valcartier.drdc-rddc.gc.ca/>
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com