Unable to build lttng module on 4.15 X-HWE-Edge kernel

[Po-Hsu Lin]

There was once a build issue in bug 1756240, fixed with 2.8.0-1ubuntu1~16.04.5
Here is another one spotted on xenial-hwe-edge kernel:

DKMS make.log for lttng-modules-2.8.0 for kernel 4.15.0-15-lowlatency (x86_64)
Fri Apr 20 10:41:30 UTC 2018
make: Entering directory '/usr/src/linux-headers-4.15.0-15-lowlatency'
Makefile:976: "Cannot use CONFIG_STACK_VALIDATION=y, please install libelf-dev, libelf-devel or elfutils-libelf-devel"
  CC [M] /var/lib/dkms/lttng-modules/2.8.0/build/lttng-ring-buffer-client-discard.o
In file included from /var/lib/dkms/lttng-modules/2.8.0/build/lttng-tracer.h:37:0,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/lttng-ring-buffer-client-discard.c:24:
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h: In function ‘trace_clock_read64’:
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h:195:34: error: implicit declaration of function ‘ACCESS_ONCE’ [-Werror=implicit-function-declaration]
  struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
                                  ^
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h:195:34: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h: In function ‘trace_clock_freq’:
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h:207:34: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
  struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
                                  ^
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h: In function ‘trace_clock_uuid’:
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h:219:34: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
  struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
                                  ^
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h: In function ‘trace_clock_name’:
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h:232:34: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
  struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
                                  ^
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h: In function ‘trace_clock_description’:
/var/lib/dkms/lttng-modules/2.8.0/build/wrapper/trace-clock.h:244:34: warning: initialization makes pointer from integer without a cast [-Wint-conversion]
  struct lttng_trace_clock *ltc = ACCESS_ONCE(lttng_trace_clock);
                                  ^
In file included from /var/lib/dkms/lttng-modules/2.8.0/build/wrapper/ringbuffer/backend_internal.h:2:0,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/lib/ringbuffer/backend.h:40,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/wrapper/ringbuffer/backend.h:1,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/lib/ringbuffer/api.h:26,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/wrapper/ringbuffer/api.h:1,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/lttng-ring-buffer-client.h:180,
                 from /var/lib/dkms/lttng-modules/2.8.0/build/lttng-ring-buffer-client-discard.c:29:
/var/lib/dkms/lttng-modules/2.8.0/build/lib/ringbuffer/backend_internal.h: In function ‘subbuffer_id_set_noref_offset’:
/var/lib/dkms/lttng-modules/2.8.0/build/lib/ringbuffer/backend_internal.h:174:20: error: lvalue required as left operand of assignment
   ACCESS_ONCE(*id) = tmp;
                    ^
cc1: some warnings being treated as errors
scripts/Makefile.build:339: recipe for target '/var/lib/dkms/lttng-modules/2.8.0/build/lttng-ring-buffer-client-discard.o' failed
make[1]: *** [/var/lib/dkms/lttng-modules/2.8.0/build/lttng-ring-buffer-client-discard.o] Error 1
Makefile:1552: recipe for target '_module_/var/lib/dkms/lttng-modules/2.8.0/build' failed
make: *** [_module_/var/lib/dkms/lttng-modules/2.8.0/build] Error 2
make: Leaving directory '/usr/src/linux-headers-4.15.0-15-lowlatency'

$ dpkg -l lttng-modules-dkms
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-===============================-====================-====================-====================================================================
ii lttng-modules-dkms 2.8.0-1ubuntu1~16.04 all Linux Trace Toolkit (LTTng) kernel modules (DKMS)

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: linux-image-4.15.0-15-lowlatency 4.15.0-15.16~16.04.1
ProcVersionSignature: User Name 4.15.0-15.16~16.04.1-lowlatency 4.15.15
Uname: Linux 4.15.0-15-lowlatency x86_64
ApportVersion: 2.20.1-0ubuntu2.16
Architecture: amd64
Date: Fri Apr 20 10:43:20 2018
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-hwe-edge
UpgradeStatus: No upgrade log present (probably fresh install)

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1765673

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.