This is the second iteration of thread-aware coredumps. Changes: - Ulrich Drepper has reviewed the data structures and checked actual coredumps via readelf - everything looks fine and according to the spec. - a serious bug has been fixed in the thread-state dumping code - it was still based on the 2.4 assumption that the task struct points to the kernel stack - it's task->thread_info in 2.5. This bug caused bogus register info to be filled in for threads. - properly wait for all threads that share the same MM to serialize with the coredumping thread. This is CLONE_VM based, not tied to CLONE_THREAD and/or signal semantics, ie. old-style (or different-style) threaded apps will be properly stopped as well. The locking might look a bit complex, but i wanted to keep the __exit_mm() overhead as low as possible. It's not quite trivial to get these bits right, because 'sharing the MM' is detached from signals semantics, so we cannot rely on broadcast-kill catching all threads. So zap_threads() iterates through every thread and zaps those which were left out. (There's a minimal race left in where a newly forked child might escape the attention of zap_threads() - this race is fixed by the OOM fixes in the mmap-speedup patch.) - fill_psinfo() is now called with the thread group leader, for the coredump to get 'process' state. - initialize the elf_thread_status structure with zeroes. the IA64 ELF bits are not included, yet, to reduce complexity of the patch. The patch has been tested on x86 UP and SMP.