mgr/ActivePyModules: fix dangling string_view in get_perf_schema_python

prev_key_name and key_name variables were declared as std::string_view but
prev_key_name was assigned from key_name, which points to
key_name_without_counter's buffer. This buffer is overwritten each iteration,
causing prev_key_name and key_name to become a dangling pointers.

This results in corrupted comparisons and can cause assertion failures like
("cursor != root" in PyFormatter::close_section) or segmentation faults
when the corrupted string is passed back to telemetry.

Fixes: https://tracker.ceph.com/issues/74286
Signed-off-by: Nitzan Mordechai <nmordech@ibm.com>

diff --git a/src/mgr/ActivePyModules.cc b/src/mgr/ActivePyModules.cc
index 0cf6aa3c1166e645a6080afefc3bc27e7b1d8e99..5ec3ccd44b38193fbf1a36d3663bfb116eca7e22 100644 (file)
--- a/src/mgr/ActivePyModules.cc
+++ b/src/mgr/ActivePyModules.cc
@@ -1152,7 +1152,7 @@ PyObject* ActivePyModules::get_perf_schema_python(
     for (auto &[key, state] : daemons) {
       std::lock_guard l(state->lock);
       with_gil(no_gil, [&, key = ceph::to_string(key), state = state] {
-       std::string_view key_name, prev_key_name;
+       std::string key_name, prev_key_name;
        perf_counter_label_pairs prev_key_labels;
        Formatter::ObjectSection counter_section(
            f, key.c_str());  // Main Object Section
@@ -1182,14 +1182,12 @@ PyObject* ActivePyModules::get_perf_schema_python(
 
          // Extract the key names from the counter path, these key names form
          // the main object section for their counters
-         string key_name_without_counter;
          if (key_labels.empty()) {
            size_t pos = counter_name_with_labels.rfind('.');
-           key_name_without_counter = counter_name_with_labels.substr(0, pos);
-           key_name = key_name_without_counter;  // key_name, osd
+           key_name = counter_name_with_labels.substr(0, pos);  // key_name, osd
          } else {
            // key_name, osd_scrub_sh_repl
-           key_name = ceph::perf_counters::key_name(counter_name_with_labels);
+           key_name = std::string(ceph::perf_counters::key_name(counter_name_with_labels));
          }
 
          /*