When creating a new thread, forgot to set its syscall_args * pointer.

src/api/thread.c

@@ -89,10 +89,20 @@ int arch_setup_new_thread(struct ktcb *new, struct ktcb *orig)
 	       (void *)((unsigned long)orig + syscall_context_offset),
 	       sizeof(syscall_context_t));
 
+	/*
+	 * Set new thread's syscall_regs offset since its
+	 * normally set during syscall entry
+	 */
+	new->syscall_regs = (syscall_context_t *)
+				((unsigned long)new + syscall_context_offset);
+
 	/*
 	 * Modify the return register value with 0 to ensure new thread
 	 * returns with that value. This is a POSIX requirement and enforces
 	 * policy on the microkernel, but it is currently the best solution.
+	 *
+	 * A cleaner but slower way would be the pager setting child registers
+	 * via exchanges_registers() and start the child thread afterwards.
 	 */
 	new->syscall_regs->r0 = 0;
 

src/arch/arm/v5/mm.c

@@ -392,7 +392,7 @@ pgd_table_t *copy_page_tables(pgd_table_t *from)
 			pgd->entry[i] |= PGD_TYPE_COARSE;
 		}
 	}
-	BUG();
+
 	return pgd;
 }