This reminds me of a strange bug I encountered once on ia64. We had a custom library that we loaded with dlopen(), and then called an initialization function w

This reminds me of a strange bug I encountered once on ia64. We had a custom library that we loaded with dlopen(), and then called an initialization function within this library. Unbeknownst to me at the time, this function created a thread which did something, and then almost immediately went to sleep for a few seconds. Also unbeknownst to me, there was also function that you were supposed to call before dlclose() to kill this thread. If you dlclosed the library without previously having called this function to stop the thread, when the thread woke up, all its code would of course be gone, and the program segfaulted, leaving a core file. Interestingly, if you ran gdb on the core file, gdb segfaulted! Presumably because the thread didn't have any corresponding code in the core file either. Took awhile to figure that one out. Curiously, on x86, all this seemingly worked fine (maybe dlclose implicitly killed the thread on x86? ... never figured out why it didn't crash on x86 but did on ia64.)