Description of problem:
While running the 32-bit version of firefox-1.5.0.10 (on AMD Opteron x86_64
platform with the Adobe Flash Plugin 9.0.31.0), the program will intermittently
freeze with "double free or corruption" after writing a backtrace and partial
memory map to the terminal. Each time, I have to SIGKILL the firefox processes
with the bottom-most child in a futex. I was running firefox on one computer
while viewing its X display on a different computer. I am including an
attachment with three different instances of this behavior.

Version-Release number of selected component (if applicable):
firefox-1.5.0.10-5.fc6.i386
firefox-1.5.0.10-5.fc6.x86_64
firefox-debuginfo-1.5.0.10-5.fc6.i386
firefox-debuginfo-1.5.0.10-5.fc6.x86_64
flash-plugin-9.0.31.0-1.i386
kernel-2.6.20-1.2944.fc6.x86_64

How reproducible:
I have not been able to predict the failure.