After much debugging, the issue is a race issue. On non-armel platforms,
shared memory operations appear to be atomic, but on ARM, on very fast
machines, these shared memory operations have a slight lag to the, which
causes the test suite failures. I'm trying to see if I can cobble
together a test suite to isolate the issue specifically.
** Also affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu Jaunty)
Importance: Undecided => High
Assignee: (unassigned) => Michael Casadevall (mcasadevall)
Status: New => Triaged
** Summary changed:
- armel build failure (without ignoring testsuite results)
+ Shared memory operations on very fast ARM hardware suffer from non-atomic
operations and race conditions.
** Description changed:
- Binary package hint: libipc-sharelite-perl
+ On extremely fast ARM boards (BogoMIPS over 900), issues involving
+ shared memory and locking crop up, and were initially discovered via
+ libipc-sharelite-perl's test suite. There is a lag in between posted a
+ value to shared memory, and then being able to retrieve it, a lag which
+ cause introduce race conditions as seen in libipc-sharelite-perl.
- http://launchpadlibrarian.net/19661148/buildlog_ubuntu-jaunty-armel
- .libipc-sharelite-perl_0.13-1build2_FAILEDTOBUILD.txt.gz
+ Original Bug Report:
+
http://launchpadlibrarian.net/19661148/buildlog_ubuntu-jaunty-armel.libipc-sharelite-perl_0.13-1build2_FAILEDTOBUILD.txt.gz
/usr/bin/make test
make[1]: Entering directory `/build/buildd/libipc-sharelite-perl-0.13'
PERL_DL_NONLAZY=1 /usr/bin/perl "-MExtUtils::Command::MM" "-e"
"test_harness(0, 'blib/lib', 'blib/arch')" t/*.t
t/00-load......# Testing IPC::ShareLite 0.13
ok
t/pod..........ok
t/sharelite....
# Failed test 'num_segments'
# at t/sharelite.t line 40.
# got: '2'
# expected: '3'
# Failed test 'lock'
# at t/sharelite.t line 71.
# got: '1008'
# expected: '2000'
# Failed test 'version inc'
# at t/sharelite.t line 72.
# got: '1012'
# expected: '2004'
# Looks like you failed 3 tests of 14.
dubious
Test returned status 3 (wstat 768, 0x300)
DIED. FAILED tests 10, 13-14
Failed 3/14 tests, 78.57% okay
Failed Test Stat Wstat Total Fail List of Failed
-------------------------------------------------------------------------------
t/sharelite.t 3 768 14 3 10 13-14
Failed 1/3 test scripts. 3/16 subtests failed.
Files=3, Tests=16, 1 wallclock secs ( 1.36 cusr + 0.08 csys = 1.44 CPU)
Failed 1/3 test programs. 3/16 subtests failed.
make[1]: *** [test_dynamic] Error 3
make[1]: Leaving directory `/build/buildd/libipc-sharelite-perl-0.13'
--
Shared memory operations on very fast ARM hardware suffer from non-atomic
operations and race conditions.
https://bugs.launchpad.net/bugs/299847
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