Bug 467214

Summary: strace -f fails to trace child process in recent kernel
Product: [Fedora] Fedora Reporter: Peter Fales <redhat.com>
Component: kernelAssignee: Kernel Maintainer List <kernel-maint>
Status: CLOSED DUPLICATE QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
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OS: Linux   
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Last Closed: 2008-10-22 05:01:49 UTC Type: ---
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Description Peter Fales 2008-10-16 12:36:06 UTC 
Description of problem:

Starting with kernel 2.6.26, "strace -f" fails to trace child processes. 

Version-Release number of selected component (if applicable):

It worked in kernel-2.6.25.14-69.fc8, and has been failing since kernel-2.6.26.3-14.fc8

How reproducible:

Very


Steps to Reproduce:

Use a simple test program, like bug.c:

  #include <stdio.h>
  main()
  {
        if ( fork() ) {
                printf("parent\n");
        } else {
                printf("child\n");
        }
  }


Then run
 
  strace -f -o strace.out ./bug


Actual results:

An error message is printed, and the child process write() does not appear
in the strace log.   Strangely, I've seen different error messages on different Fedora 8 systems, either:

  PANIC: attached pid 26968 exited
or
  resume: ptrace(PTRACE_SYSCALL, ...): No such process
  

Expected results:

  No error message is printed, and the write("child") appears in the 
  strace.out file


Additional info:

Even though the error comes from strace, I'm assuming that it's actually a problem with the kernel, because reverting to an earlier kernel version causes the problem to go away.

I'm seeing the problem in both Fedora 8 and Fedora 9, and in both cases it starts showing up in the 2.6.26.* kernels
Comment 1 Chuck Ebbert 2008-10-22 05:01:49 UTC 

*** This bug has been marked as a duplicate of bug 461552 ***