Bug 193870 - Large data-set perl script which forks child processes will coredump near exit()
Summary: Large data-set perl script which forks child processes will coredump near exit()
Status: New
Alias: None
Product: Base System
Classification: Unclassified
Component: kern (show other bugs)
Version: 10.0-RELEASE
Hardware: amd64 Any
: --- Affects Some People
Assignee: freebsd-bugs (Nobody)
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2014-09-23 12:40 UTC by lsim4242
Modified: 2014-09-23 12:49 UTC (History)
0 users

See Also:

Attachments
script_to_core_dump (1.71 KB, text/plain)
2014-09-23 12:49 UTC, lsim4242 		no flags Details
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Description lsim4242 2014-09-23 12:40:22 UTC 
Hi,
I do not know whether I should be 'bugging' to the perl mob, or
to the FreeBSD amd64 group.

Well here goes.  I am able to reduce the core-dumping problem to a perl script
which can be used to generate the problem.

Basically, you have a perl script which chews up N byte size of memory,
then forks out a few child processes (in my case 2). Then each child
does an 'exit(0)'. The parent then 'wait()' for each child and then exit.

Where N can be larger than (Your real memory/number of child forks).
This is to force the swap space to be used.

On running this script on (Fbsd 10.0-RELEASE-p3 amd64) perl v5.16.3,
the script will core-dump.

Additional info:
** On i386 FreeBSD versions, the core-dump does *not* happen including
   Fbsd 10.0 i386

** As I have only recently started using amd64, I do not know if this
   problem also exist in prior versions of Fbsd 10.0 amd64.

** I also wrote a C version, and that ran fine on the amd64 OS!

Please help as I really would like to used amd64 instead of i386 versions
of Fbsd.

Thanks
sim
Comment 1 lsim4242 2014-09-23 12:49:41 UTC 
Created attachment 147596 [details]
script_to_core_dump