Child processes that call an exec function on a Microsoft Win32-based binary executable file remain as zombie processes and consume process slots. Therefore, the Microsoft Interix subsystem eventually runs out of process slots and does not let new processes create.

In particular, the tcsh command shell does not succeed while it tries to create many pipes to Win32 processes. Additionally, you may receive the following error message: Note This problem occurs only with Win32-executable files. This problem does not occur with equivalent Interix-executable files.

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Hotfix information

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, submit a request to Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language.

Prerequisites

No prerequisites are required.

Restart requirement

You must restart your computer after you apply this hotfix.

File information

The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.

   Date         Time   Version            Size    File name
   --------------------------------------------------------------
   07-May-2004  01:46  8.0.1969.6        763,904  Psxss.exe        

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The Korn shell seems to be less vulnerable to this problem than the C shell because of the way that the Korn shell forks processes. Therefore, a workaround for C shell scripts is to convert them to Korn shell scripts.

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Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

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Sample code

The following sample code demonstrates this problem. Compile the Test1.c code as a Windows executable, and then run the Test.csh code.

Test1.c code

/* test1.c */
#include <stdio.h>
int main(int argc, char* argv[])
{
  int c;
  while( ( c = getchar()) != EOF )
    putchar( c ) ;
  return 0 ;
}

Test.csh code

#!/bin/csh
# 
# test.csh
#
while ( 1 )
set RESULT = `printf "a b c" | ./test1.exe`
echo $RESULT
end

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