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

Bug #501454 reported by gmoore777 on 2009-12-29
This bug affects 1 person
Affects Status Importance Assigned to Milestone
strace (Ubuntu)

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;


<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"/>
@echo "Inside Makefile doing the target of makeTarget.\n"


If I change JAVA_HOME to a 64 bit java, then strace completes
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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