> I added some loops in the parent and child threads. I also added code > in the child thread to watch the return point location on the stack > for start_thread. What I found is the stack gets overwritten after > the thread has started. At the same time, the parent is looping > post fork. More debugging. It seems bad news to have more than one clone syscall active at a time. The thread child may still be in the kernel when the fork syscall is made by the parent. The testcase doesn't fail if the parent waits for the child thread to start. See below. Dave -- J. David Anglin dave.anglin@xxxxxxxxxxxxxx National Research Council of Canada (613) 990-0752 (FAX: 952-6602) #include <pthread.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> /* http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=561203 clone(child_stack=0x4088d040, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, parent_tidptr=0x4108c4e8, tls=0x4108c900, child_tidptr=0x4108c4e8) = 14819 [pid 14819] set_robust_list(0x4108c4f0, 0xc) = 0 [pid 14818] clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0x40002028) = 14820 g++ minifail.cpp -o minifail -O0 -pthread -g i=0; while true; do i=$(($i+1)); echo Run $i; ./minifail; done; */ static volatile int run; void* thread_run(void* arg) { static long status; int i; run = 1; pthread_yield(); for (i = 10000000; i; i--) continue; write(1,"Thread OK.\n",11); return (void *)&status; } int pure_test() { pthread_t thread; pthread_create(&thread, NULL, thread_run, NULL); while (!run) continue; switch (fork()) { case -1: perror("fork() failed"); case 0: write(1,"Child OK.\n",10); _exit(0); default: break; } pthread_join(thread, NULL); return 0; } int main(int argc, char** argv) { return pure_test(); } -- To unsubscribe from this list: send the line "unsubscribe linux-parisc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
