[cmake-developers] kernel log segfault warning messages when building/testing CMake

[Alan W. Irwin]

My "merlin" computer automatically builds and tests (including the
PLplot contract test) CMake each day at 4:32 Pacific time, and I have
noticed for some time now that those successful "merlin" tests (clean for the
CMake dashboard, but with 8 compile warnings but no errors for the
KWSys dashboard that is also generated by the CMake test) are always
accompanied by segfault warnings in the kernel log file for my Debian
Buster system.  At least some of those segfaults seem to
be associated with the KWSys part of this test.  Here are those log
warnings for today (taken from /var/log/messages):

======================
Oct 23 04:32:47 merlin kernel: [145023.933476] cmsysTestProces[5466]: segfault at 4 ip 000055d23f362e3b sp 00007ffda48d1940
  error 6 in cmsysTestProcess[55d23f362000+6000]
Oct 23 04:32:47 merlin kernel: [145023.933483] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 f
f ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00

Oct 23 04:32:47 merlin kernel: [145023.935919] cmsysTestProces[5472]: segfault at 4 ip 000055b7f515be3b sp 00007ffd46054c90
  error 6 in cmsysTestProcess[55b7f515b000+6000]
Oct 23 04:32:47 merlin kernel: [145023.935928] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 f
f ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00

Oct 23 04:33:48 merlin kernel: [145084.853316] Crash[6355]: segfault at 0 ip 000055f36cfd8135 sp 00007ffcc0d2d0f0 error 6 i
n Crash[55f36cfd8000+1000]
Oct 23 04:33:48 merlin kernel: [145084.853321] Code: 2f 00 00 01 5d c3 0f 1f 80 00 00 00 00 c3 0f 1f 80 00 00 00 00 e9 7b f
f ff ff 55 48 89 e5 48 c7 45 f8 00 00 00 00 48 8b 45 f8 <c7> 00 01 00 00 00 b8 00 00 00 00 5d c3 66 2e 0f 1f 84 00 00 00 00

Oct 23 04:34:33 merlin kernel: [145130.287867] kwsysTestProces[2964]: segfault at 4 ip 0000557e9dadce3b sp 00007fff85d3cce0 error 6 in kwsysTestProcess[557e9dadc000+6000]
Oct 23 04:34:33 merlin kernel: [145130.287875] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 ff ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00 
Oct 23 04:34:35 merlin kernel: [145131.727495] kwsysTestProces[4382]: segfault at 4 ip 000055ccd8790e3b sp 00007ffc422fea20 error 6 in kwsysTestProcess[55ccd8790000+6000]
Oct 23 04:34:35 merlin kernel: [145131.727499] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 ff ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00 
Oct 23 04:35:12 merlin kernel: [145169.367275] kwsysTestProces[4838]: segfault at 4 ip 0000563d98a43e3b sp 00007ffce04a4ab0 error 6 in kwsysTestProcess[563d98a43000+6000]
Oct 23 04:35:12 merlin kernel: [145169.367279] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 ff ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00 
Oct 23 04:41:17 merlin kernel: [145533.853387] kwsysTestProces[17736]: segfault at 4 ip 000056237dea3e3b sp 00007ffc5cd97cf0 error 6 in kwsysTestProcess[56237dea3000+6000]
Oct 23 04:41:17 merlin kernel: [145533.853394] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 ff ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00 
Oct 23 04:41:17 merlin kernel: [145533.855467] kwsysTestProces[17742]: segfault at 4 ip 000055ae9d89ce3b sp 00007fff23ff8b30 error 6 in kwsysTestProcess[55ae9d89c000+6000]
Oct 23 04:41:17 merlin kernel: [145533.855473] Code: 00 48 8d 3d 6f 56 00 00 e8 12 f5 ff ff 48 8b 3d db 83 00 00 e8 76 f4 ff ff 48 8b 3d ef 83 00 00 e8 6a f4 ff ff ba 2e 00 00 00 <c7> 04 25 04 00 00 00 00 00 00 00 48 8b 0d b3 83 00 00 be 01 00 00

======================

I don't notice any other platform on KWSys dashboard that also has the
8 build warnings, but it is likely my fairly recent gcc compiler
(Debian Buster ccache and gcc/g++ 8.2.0) is more sensitive to
problematic code in KWSys than prior versions of the gcc compiler
suite.

Anyhow, I suggest cleaning up the 8 build warnings for the KWSys
code to see if those are the source of some/all of these
segfaults.  And if no CMake developer here has access to Debian Buster, I
would be glad to run preliminary tests of any of your proposed KWSys code
changes to make sure the compile warnings are gone.

I have attached a compressed version of the my_dashboard.cmake script
that created a while ago (with lots of advice from Brad) to configure
this CMake test in case there is anything problematic in there.  For
example, I notice

set(ENV{CXXFLAGS} "-O3 -DNDEBUG")
set(ENV{CFLAGS} "-O3 -DNDEBUG")

in there in case that makes a difference with regard to the above KWSys compile warnings
that seem to appear just for my platform.

Alan
__________________________
Alan W. Irwin

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).
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