diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 563e80f9006a438442dcfb1736e846aca7959b63..a8505d84b76ea1e4b959827e1c79a0f3e8d70b87 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4815,11 +4815,11 @@ static const char readme_msg[] =
#endif
#endif /* CONFIG_STACK_TRACER */
#ifdef CONFIG_DYNAMIC_EVENTS
- " dynamic_events\t\t- Add/remove/show the generic dynamic events\n"
+ " dynamic_events\t\t- Create/append/remove/show the generic dynamic events\n"
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
#ifdef CONFIG_KPROBE_EVENTS
- " kprobe_events\t\t- Add/remove/show the kernel dynamic events\n"
+ " kprobe_events\t\t- Create/append/remove/show the kernel dynamic events\n"
"\t\t\t Write into this file to define/undefine new trace events.\n"
#endif
#ifdef CONFIG_UPROBE_EVENTS
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index e8f72431b866294218b1cf113ff77e5935ee276a..f43098bf62dd49018a617cd9256b62c932e51d90 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -492,6 +492,10 @@ static void __unregister_trace_kprobe(struct trace_kprobe *tk)
/* Unregister a trace_probe and probe_event */
static int unregister_trace_kprobe(struct trace_kprobe *tk)
{
+ /* If other probes are on the event, just unregister kprobe */
+ if (trace_probe_has_sibling(&tk->tp))
+ goto unreg;
+
/* Enabled event can not be unregistered */
if (trace_probe_is_enabled(&tk->tp))
return -EBUSY;
@@ -500,12 +504,38 @@ static int unregister_trace_kprobe(struct trace_kprobe *tk)
if (unregister_kprobe_event(tk))
return -EBUSY;
+unreg:
__unregister_trace_kprobe(tk);
dyn_event_remove(&tk->devent);
+ trace_probe_unlink(&tk->tp);
return 0;
}
+static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
+{
+ int ret;
+
+ /* Append to existing event */
+ ret = trace_probe_append(&tk->tp, &to->tp);
+ if (ret)
+ return ret;
+
+ /* Register k*probe */
+ ret = __register_trace_kprobe(tk);
+ if (ret == -ENOENT && !trace_kprobe_module_exist(tk)) {
+ pr_warn("This probe might be able to register after target module is loaded. Continue.\n");
+ ret = 0;
+ }
+
+ if (ret)
+ trace_probe_unlink(&tk->tp);
+ else
+ dyn_event_add(&tk->devent);
+
+ return ret;
+}
+
/* Register a trace_probe and probe_event */
static int register_trace_kprobe(struct trace_kprobe *tk)
{
@@ -514,14 +544,24 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
mutex_lock(&event_mutex);
- /* Delete old (same name) event if exist */
old_tk = find_trace_kprobe(trace_probe_name(&tk->tp),
trace_probe_group_name(&tk->tp));
if (old_tk) {
- ret = unregister_trace_kprobe(old_tk);
- if (ret < 0)
- goto end;
- free_trace_kprobe(old_tk);
+ if (trace_kprobe_is_return(tk) != trace_kprobe_is_return(old_tk)) {
+ trace_probe_log_set_index(0);
+ trace_probe_log_err(0, DIFF_PROBE_TYPE);
+ ret = -EEXIST;
+ } else {
+ ret = trace_probe_compare_arg_type(&tk->tp, &old_tk->tp);
+ if (ret) {
+ /* Note that argument starts index = 2 */
+ trace_probe_log_set_index(ret + 1);
+ trace_probe_log_err(0, DIFF_ARG_TYPE);
+ ret = -EEXIST;
+ } else
+ ret = append_trace_kprobe(tk, old_tk);
+ }
+ goto end;
}
/* Register new event */
@@ -755,7 +795,7 @@ static int trace_kprobe_create(int argc, const char *argv[])
trace_probe_log_err(0, BAD_INSN_BNDRY);
else if (ret == -ENOENT)
trace_probe_log_err(0, BAD_PROBE_ADDR);
- else if (ret != -ENOMEM)
+ else if (ret != -ENOMEM && ret != -EEXIST)
trace_probe_log_err(0, FAIL_REG_PROBE);
goto error;
}
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index 28733bd6b607e7c0ca46db803c957f04620e4c6b..651a1449acdee084870f8044a13da62a2cbd1aa8 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -886,6 +886,35 @@ int traceprobe_define_arg_fields(struct trace_event_call *event_call,
return 0;
}
+static void trace_probe_event_free(struct trace_probe_event *tpe)
+{
+ kfree(tpe->class.system);
+ kfree(tpe->call.name);
+ kfree(tpe->call.print_fmt);
+ kfree(tpe);
+}
+
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to)
+{
+ if (trace_probe_has_sibling(tp))
+ return -EBUSY;
+
+ list_del_init(&tp->list);
+ trace_probe_event_free(tp->event);
+
+ tp->event = to->event;
+ list_add_tail(&tp->list, trace_probe_probe_list(to));
+
+ return 0;
+}
+
+void trace_probe_unlink(struct trace_probe *tp)
+{
+ list_del_init(&tp->list);
+ if (list_empty(trace_probe_probe_list(tp)))
+ trace_probe_event_free(tp->event);
+ tp->event = NULL;
+}
void trace_probe_cleanup(struct trace_probe *tp)
{
@@ -894,15 +923,8 @@ void trace_probe_cleanup(struct trace_probe *tp)
for (i = 0; i < tp->nr_args; i++)
traceprobe_free_probe_arg(&tp->args[i]);
- if (tp->event) {
- struct trace_event_call *call = trace_probe_event_call(tp);
-
- kfree(tp->event->class.system);
- kfree(call->name);
- kfree(call->print_fmt);
- kfree(tp->event);
- tp->event = NULL;
- }
+ if (tp->event)
+ trace_probe_unlink(tp);
}
int trace_probe_init(struct trace_probe *tp, const char *event,
@@ -1006,3 +1028,22 @@ int trace_probe_remove_file(struct trace_probe *tp,
return 0;
}
+
+/*
+ * Return the smallest index of different type argument (start from 1).
+ * If all argument types and name are same, return 0.
+ */
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b)
+{
+ int i;
+
+ for (i = 0; i < a->nr_args; i++) {
+ if ((b->nr_args <= i) ||
+ ((a->args[i].type != b->args[i].type) ||
+ (a->args[i].count != b->args[i].count) ||
+ strcmp(a->args[i].name, b->args[i].name)))
+ return i + 1;
+ }
+
+ return 0;
+}
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index 0b84abb884c2bbd1985f42bef7fc26c38747bfeb..39926e8a344b5aa93864abed5253d46a10c81ec5 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -302,6 +302,13 @@ static inline struct list_head *trace_probe_probe_list(struct trace_probe *tp)
return &tp->event->probes;
}
+static inline bool trace_probe_has_sibling(struct trace_probe *tp)
+{
+ struct list_head *list = trace_probe_probe_list(tp);
+
+ return !list_empty(list) && !list_is_singular(list);
+}
+
static inline int trace_probe_unregister_event_call(struct trace_probe *tp)
{
/* tp->event is unregistered in trace_remove_event_call() */
@@ -316,12 +323,15 @@ static inline bool trace_probe_has_single_file(struct trace_probe *tp)
int trace_probe_init(struct trace_probe *tp, const char *event,
const char *group);
void trace_probe_cleanup(struct trace_probe *tp);
+int trace_probe_append(struct trace_probe *tp, struct trace_probe *to);
+void trace_probe_unlink(struct trace_probe *tp);
int trace_probe_register_event_call(struct trace_probe *tp);
int trace_probe_add_file(struct trace_probe *tp, struct trace_event_file *file);
int trace_probe_remove_file(struct trace_probe *tp,
struct trace_event_file *file);
struct event_file_link *trace_probe_get_file_link(struct trace_probe *tp,
struct trace_event_file *file);
+int trace_probe_compare_arg_type(struct trace_probe *a, struct trace_probe *b);
#define trace_probe_for_each_link(pos, tp) \
list_for_each_entry(pos, &(tp)->event->files, list)
@@ -419,7 +429,9 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
C(ARG_TOO_LONG, "Argument expression is too long"), \
C(NO_ARG_BODY, "No argument expression"), \
C(BAD_INSN_BNDRY, "Probe point is not an instruction boundary"),\
- C(FAIL_REG_PROBE, "Failed to register probe event"),
+ 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"),
#undef C
#define C(a, b) TP_ERR_##a