tracing/eprobe: Show syntax error logs in error_log file

Show the syntax errors for event probes in error_log file as same as
other dynamic events, so that user can understand what is the problem.

Link: https://lkml.kernel.org/r/165932113556.2850673.3483079297896607612.stgit@devnote2
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index a30f214..4a0e9d9 100644 (file)
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -839,8 +839,11 @@ static int trace_eprobe_tp_update_arg(struct trace_eprobe *ep, const char *argv[
        if (ret)
                return ret;
 
-       if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG)
+       if (ep->tp.args[i].code->op == FETCH_OP_TP_ARG) {
                ret = trace_eprobe_tp_arg_update(ep, i);
+               if (ret)
+                       trace_probe_log_err(0, BAD_ATTACH_ARG);
+       }
 
        return ret;
 }
@@ -880,8 +883,10 @@ static int __trace_eprobe_create(int argc, const char *argv[])
        trace_probe_log_set_index(1);
        sys_event = argv[1];
        ret = traceprobe_parse_event_name(&sys_event, &sys_name, buf2, 0);
-       if (!sys_event || !sys_name)
+       if (!sys_event || !sys_name) {
+               trace_probe_log_err(0, NO_EVENT_INFO);
                goto parse_error;
+       }
 
        if (!event) {
                strscpy(buf1, argv[1], MAX_EVENT_NAME_LEN);
@@ -896,6 +901,8 @@ static int __trace_eprobe_create(int argc, const char *argv[])
 
        if (IS_ERR(ep)) {
                ret = PTR_ERR(ep);
+               if (ret == -ENODEV)
+                       trace_probe_log_err(0, BAD_ATTACH_EVENT);
                /* This must return -ENOMEM or missing event, else there is a bug */
                WARN_ON_ONCE(ret != -ENOMEM && ret != -ENODEV);
                ep = NULL;

diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 92cc149..3b3869a 100644 (file)
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -442,7 +442,10 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
        C(FAIL_REG_PROBE,       "Failed to register probe event"),\
        C(DIFF_PROBE_TYPE,      "Probe type is different from existing probe"),\
        C(DIFF_ARG_TYPE,        "Argument type or name is different from existing probe"),\
-       C(SAME_PROBE,           "There is already the exact same probe event"),
+       C(SAME_PROBE,           "There is already the exact same probe event"),\
+       C(NO_EVENT_INFO,        "This requires both group and event name to attach"),\
+       C(BAD_ATTACH_EVENT,     "Attached event does not exist"),\
+       C(BAD_ATTACH_ARG,       "Attached event does not have this field"),
 
 #undef C
 #define C(a, b)                TP_ERR_##a