}
/*
+ * To prevent the comm cache from being overwritten when no
+ * tracing is active, only save the comm when a trace event
+ * occurred.
+ */
+static DEFINE_PER_CPU(bool, trace_cmdline_save);
+
+/*
* Kill all tracing for good (never come back).
* It is initialized to 1 but will turn to zero if the initialization
* of the tracer is successful. But that is the only place that sets
!tracing_is_on())
return;
+ if (!__this_cpu_read(trace_cmdline_save))
+ return;
+
+ __this_cpu_write(trace_cmdline_save, false);
+
trace_save_cmdline(tsk);
}
return event;
}
+void
+__buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event)
+{
+ __this_cpu_write(trace_cmdline_save, true);
+ ring_buffer_unlock_commit(buffer, event);
+}
+
static inline void
__trace_buffer_unlock_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event,
unsigned long flags, int pc,
int wake)
{
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
ftrace_trace_userstack(buffer, flags, pc);
unsigned long flags, int pc,
struct pt_regs *regs)
{
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack_regs(buffer, flags, 0, pc, regs);
ftrace_trace_userstack(buffer, flags, pc);
entry->parent_ip = parent_ip;
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
}
void
entry->size = trace.nr_entries;
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
out:
/* Again, don't let gcc optimize things here */
save_stack_trace_user(&trace);
if (!filter_check_discard(call, entry, buffer, event))
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
out_drop_count:
__this_cpu_dec(user_stack_count);
memcpy(entry->buf, tbuffer, sizeof(u32) * len);
if (!filter_check_discard(call, entry, buffer, event)) {
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
memcpy(&entry->buf, tbuffer, len);
entry->buf[len] = '\0';
if (!filter_check_discard(call, entry, buffer, event)) {
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
ftrace_trace_stack(buffer, flags, 6, pc);
}
out:
} else
entry->buf[cnt] = '\0';
- ring_buffer_unlock_commit(buffer, event);
+ __buffer_unlock_commit(buffer, event);
written = cnt;