[Bug 501454] Re: strace hangs if tracing 32 bit app that spawns 64 bit apps

[Adrien Nader]

I think that if this has not been fixed, this is not relevant anymore as
people would instead strace from the 64-bit side. Moreover, these cross-
world operations can be very difficult and are unlikely to change
further in the future even if this still happens.

** Changed in: strace (Ubuntu)
       Status: New => Won't Fix

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https://bugs.launchpad.net/bugs/501454

Title:
  strace hangs if tracing 32 bit app that spawns 64 bit apps

Status in strace package in Ubuntu:
  Won't Fix

Bug description:
  Binary package hint: strace

  [HardyHeron 64-bit]

  When running 64bit strace on 64 bit HardyHeron (or LucidLynx)
  it hangs when following 32-bit java.(an Ant build process)

  I've narrowed down the problem to these basic steps:

  The command I run is:
  export JAVA_HOME=/opt/jdk1.6.0_16_32; #(a 32-bit java installation)
  strace -f -F -e open,chdir,fchdir,fork,vfork,exit_group,execve,_ex it <path_to_ant>/bin/ant -f build.xml target1;

  ------------------------------------------
  build.xml:

  <project name="main" default="target1">
  <target name="target1">
  <echo message="Inside ant target of target1."/>
  <exec executable="make" failonerror="true" dir=".">
  <arg line="-f Makefile makeTarget"/>
  </exec>
  </target>
  </project>
  ------------------------------------------
  Makefile:
  makeTarget:
  @echo "Inside Makefile doing the target of makeTarget.\n"

  ----------------------------

  If I change JAVA_HOME to a 64 bit java, then strace completes
  successfully.
  Otherwise it hangs, until I `kill -9` the java process.

  ----------------------------
  I've searched the forums and found only one other pertinent
  post about how 64 bit strace could not follow vforks, but
  that has been fixed in a version of strace that is available and installed on my LucidLynx machine, and my problem exists as well on LucidLynx.
  ----------------------------
  I narrowed down problem a bit more.
  In that above build.xml file. If I change from running `make`, to running `ls`, I get the same hanging problem.

  But if I copy a 32-bit "ls" from another machine and run
  that instead then strace completes successfully.

  Meaning, the 64-bit strace command can't trace a 32 bit java application (ant) that spawns off 64-bit binaries.
  Everything needs to be all 32-bit. (or all 64 bit)

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