tracing/probe: Reject exactly same probe event
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>
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 0ba3239..a6697e2 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -528,10 +528,53 @@
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 @@
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;
}
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index f805cc4..4ee7037 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -436,7 +436,8 @@
C(BAD_INSN_BNDRY, "Probe point is not an instruction boundary"),\
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(DIFF_ARG_TYPE, "Argument type or name is different from existing probe"),\
+ C(SAME_PROBE, "There is already the exact same probe event"),
#undef C
#define C(a, b) TP_ERR_##a
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index cbf4da4b..34dd6d0 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -410,10 +410,53 @@
return 0;
}
+static bool trace_uprobe_has_same_uprobe(struct trace_uprobe *orig,
+ struct trace_uprobe *comp)
+{
+ struct trace_probe_event *tpe = orig->tp.event;
+ struct trace_probe *pos;
+ struct inode *comp_inode = d_real_inode(comp->path.dentry);
+ int i;
+
+ list_for_each_entry(pos, &tpe->probes, list) {
+ orig = container_of(pos, struct trace_uprobe, tp);
+ if (comp_inode != d_real_inode(orig->path.dentry) ||
+ comp->offset != orig->offset)
+ 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_uprobe(struct trace_uprobe *tu, struct trace_uprobe *to)
{
int ret;
+ ret = trace_probe_compare_arg_type(&tu->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_uprobe_has_same_uprobe(to, tu)) {
+ trace_probe_log_set_index(0);
+ trace_probe_log_err(0, SAME_PROBE);
+ return -EEXIST;
+ }
+
/* Append to existing event */
ret = trace_probe_append(&tu->tp, &to->tp);
if (!ret)
@@ -469,14 +512,7 @@
trace_probe_log_err(0, DIFF_PROBE_TYPE);
ret = -EEXIST;
} else {
- ret = trace_probe_compare_arg_type(&tu->tp, &old_tu->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_uprobe(tu, old_tu);
+ ret = append_trace_uprobe(tu, old_tu);
}
goto end;
}
