[petsc-users] Strange Segmentation Violation error

[TAY wee-beng]

Hi,

I have been PETSc together with my CFD code. There seems to be a bug 
with the Intel compiler such that when I call some DM routines such as 
DMLocalToLocalBegin, a segmentation violation will occur if full 
optimization is used. I had posted this question a while back. So the 
current solution is to use -O1 -ip instead of -O3 -ipo -ip for certain 
source files which uses DMLocalToLocalBegin etc.

Recently, I made some changes to the code, mainly adding some stuffs. 
However, depending on my options. some cases still go thru the same 
program path.

Now when I tried to run those same cases, I got segmentation violation, 
which didn't happen before:

/ IIB_I_cell_no_uvw_total2          14          10 6           3//
//           2           1/

/[0]PETSC ERROR: 
------------------------------------------------------------------------//
//[0]PETSC ERROR: Caught signal number 11 SEGV: Segmentation Violation, 
probably memory access out of range//
//[0]PETSC ERROR: Try option -start_in_debugger or 
-on_error_attach_debugger//
//[0]PETSC ERROR: or see 
http://www.mcs.anl.gov/petsc/documentation/faq.html#valgrind//
//[0]PETSC ERROR: or try http://valgrind.org on GNU/linux and Apple Mac 
OS X to find memory corruption errors//
//[0]PETSC ERROR: configure using --with-debugging=yes, recompile, link, 
and run //
//[0]PETSC ERROR: to get more information on the crash.//
//[0]PETSC ERROR: --------------------- Error Message 
--------------------------------------------------------------//
//[0]PETSC ERROR: Signal received//
//[0]PETSC ERROR: See 
http://www.mcs.anl.gov/petsc/documentation/faq.html for trouble shooting.//
//[0]PETSC ERROR: Petsc Release Version 3.7.4, Oct, 02, 2016 //
//[0]PETSC ERROR: ./a.out /

I can't debug using VS since the codes have been optimized. I tried to 
print messages (if (myid == 0) print "1") to pinpoint the error. 
Strangely, after adding these print messages, the error disappears.

/ IIB_I_cell_no_uvw_total2          14          10 6           3//
//           2           1//
// 1//
// 2//
// 3//
// 4//
// 5//
//    1      0.26873613      0.12620288      0.12949340 1.11422363  
0.43983516E-06 -0.59311066E-01  0.25546227E+04//
//    2      0.22236892      0.14528589      0.16939270 1.10459102  
0.74556128E-02 -0.55168234E-01  0.25532419E+04//
//    3      0.20764796      0.14832689      0.18780489 1.08039569  
0.80299767E-02 -0.46972411E-01  0.25523174E+04/

Can anyone give a logical explanation why this is happening? Moreover, 
if I removed printing 1 to 3, and only print 4 and 5, segmentation 
violation appears again.

I am using Intel Fortran 2016.1.150. I wonder if it helps if I post in 
the Intel Fortran forum.

I can provide more info if require.


-- 
Thank you very much.

Yours sincerely,

================================================
TAY Wee-Beng (Zheng Weiming) 郑伟明
Personal research webpage: http://tayweebeng.wixsite.com/website
Youtube research showcase: https://www.youtube.com/channel/UC72ZHtvQNMpNs2uRTSToiLA
linkedin: www.linkedin.com/in/tay-weebeng
================================================

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