static int __init mod_init( void ) { void *p; rcu_read_lock_sched(); p = rcu_dereference_sched( test_pointer ); rcu_read_unlock_sched(); return 0; }
static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) { struct trace_array *tr = data; struct ftrace_event_file *ftrace_file; struct syscall_trace_enter *entry; struct syscall_metadata *sys_data; struct ring_buffer_event *event; struct ring_buffer *buffer; unsigned long irq_flags; int pc; int syscall_nr; int size; syscall_nr = trace_get_syscall_nr(current, regs); if (syscall_nr < 0 || syscall_nr >= NR_syscalls) return; /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */ ftrace_file = rcu_dereference_sched(tr->enter_syscall_files[syscall_nr]); if (!ftrace_file) return; if (ftrace_trigger_soft_disabled(ftrace_file)) return; sys_data = syscall_nr_to_meta(syscall_nr); if (!sys_data) return; size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args; local_save_flags(irq_flags); pc = preempt_count(); buffer = tr->trace_buffer.buffer; event = trace_buffer_lock_reserve(buffer, sys_data->enter_event->event.type, size, irq_flags, pc); if (!event) return; entry = ring_buffer_event_data(event); entry->nr = syscall_nr; syscall_get_arguments(current, regs, 0, sys_data->nb_args, entry->args); event_trigger_unlock_commit(ftrace_file, buffer, event, entry, irq_flags, pc); }