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tracing/probe: Reject exactly same probe event

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Reject exactly same probe events as existing probes.

Multiprobe allows user to define multiple probes on same
event. If user appends a probe which exactly same definition
(same probe address and same arguments) on existing event,
the event will record same probe information twice.
That can be confusing users, so reject it.

Link: http://lkml.kernel.org/r/156879694602.31056.5533024778165036763.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Masami Hiramatsu
2019-09-18 17:55:46 +09:00
committed by Steven Rostedt (VMware)
parent 44d00dc7ce
commit fe60b0ce8e
3 changed files with 90 additions and 17 deletions
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52
kernel/trace/trace_kprobe.c
View File

@@ -528,10 +528,53 @@ unreg:
return 0;
}
static bool trace_kprobe_has_same_kprobe(struct trace_kprobe *orig,
struct trace_kprobe *comp)
{
struct trace_probe_event *tpe = orig->tp.event;
struct trace_probe *pos;
int i;
list_for_each_entry(pos, &tpe->probes, list) {
orig = container_of(pos, struct trace_kprobe, tp);
if (strcmp(trace_kprobe_symbol(orig),
trace_kprobe_symbol(comp)) ||
trace_kprobe_offset(orig) != trace_kprobe_offset(comp))
continue;
/*
* trace_probe_compare_arg_type() ensured that nr_args and
* each argument name and type are same. Let's compare comm.
*/
for (i = 0; i < orig->tp.nr_args; i++) {
if (strcmp(orig->tp.args[i].comm,
comp->tp.args[i].comm))
continue;
}
return true;
}
return false;
}
static int append_trace_kprobe(struct trace_kprobe *tk, struct trace_kprobe *to)
{
int ret;
ret = trace_probe_compare_arg_type(&tk->tp, &to->tp);
if (ret) {
/* Note that argument starts index = 2 */
trace_probe_log_set_index(ret + 1);
trace_probe_log_err(0, DIFF_ARG_TYPE);
return -EEXIST;
}
if (trace_kprobe_has_same_kprobe(to, tk)) {
trace_probe_log_set_index(0);
trace_probe_log_err(0, SAME_PROBE);
return -EEXIST;
}
/* Append to existing event */
ret = trace_probe_append(&tk->tp, &to->tp);
if (ret)
@@ -568,14 +611,7 @@ static int register_trace_kprobe(struct trace_kprobe *tk)
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);
ret = append_trace_kprobe(tk, old_tk);
}
goto end;
}