[Novalug] RHEL x86_64 Absoft10.0 FORTRAN 90 question

Megan Larko larkoc@iges.org
Fri Feb 16 12:29:50 EST 2007


Hi,

I have a user who came to me today with a error running his code:
  *** glibc detected *** double free or corruption (out): 0x000000001480df70 ***

A Google search indicated to try a simple recompile and run again; no change.
Next step, run debugger.  So we invoked the Absoft version 10.0 Fx3 GUI debugger.  The information 
given is that the code is failing on a deallocate(varname) statement on line 540.  The specific 
string from the debugger is "Process unnamed (p1) is stopped at 0x3dcc72e21d on signal SIGABRT
__GI_raise+0x003d  cmpq        $-4096,%rax
Process unnamed (p1) has exited during fork/exec sequence"

The user thinks it is an OS glitch.  However this code ran yesterday on two independent RHEL x86_64 
boxes and today runs on neither.  One of the two boxes was rebooted for other reasons this morning.
The user states that only comments in the code were changed prior to the re-compile.  The user 
cannot roll back to yesterdays version because he was not using any versioning software and there 
are too many changes to look for/remember (in the comments).  As it ran yesterday on a box which is 
unchanged between yesterday and today as well as both computers giving the same error message, I am 
of the opinion that the error is a typo in the code rather than having found an OS bug.  Could I be 
wrong?

A Google search of "Process unnamed (p1) has exited during fork/exec sequence" turned up nothing 
interesting (only 6 matches!).

How can I guide the user to find why this code no longer runs when "only comments were changed"?
How can I help identify what might be a badly typed comment line?  Why would one deallocate 
statement segfault a job and generate a "glibc detected" message?  (I really don't wish to get too 
deep into 10000 lines of modelling code.    Really I saw it running on the system until this morning.)

The system is:
[larkoc@crew01 ~]$ uname -a
Linux crew01.iges.org 2.6.9-42.0.2.EL_lustre.1.4.7.3smp #1 SMP Fri Nov 10 18:59:29 MST 2006 x86_64 
x86_64 x86_64 GNU/Linux

The compiler is Absoft version 10.0.

I appreciate any tact and suggestions the List has to offer.

Thanks!
megan



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