Fix segfault in profiler-cpu-log and profiler-memory-log (bug#78763)

* src/profiler.c (export_log): Check if a log has been allocated first,
and return nil if it hasn't.
(Fprofiler_cpu_log, Fprofiler_memory_log): Doc fix.
* test/src/profiler-tests.el (profiler-tests-cpu-profiler)
(profiler-tests-memory-profiler): New tests.

1 files changed, 11 insertions, 2 deletions

diff --git a/src/profiler.c b/src/profiler.c
index 12d75012c79..f421eb52b31 100644
--- a/src/profiler.c
+++ b/src/profiler.c
@@ -534,7 +534,11 @@ DEFUN ("profiler-cpu-log", Fprofiler_cpu_log, Sprofiler_cpu_log,
 The log is a hash-table mapping backtraces to counters which represent
 the amount of time spent at those points.  Every backtrace is a vector
 of functions, where the last few elements may be nil.
-Before returning, a new log is allocated for future samples.  */)
+
+If the profiler has not run since the last invocation of
+`profiler-cpu-log' (or was never run at all), return nil.  If the
+profiler is currently running, allocate a new log for future samples
+before returning.  */)
   (void)
 {
   /* Temporarily stop profiling to avoid it interfering with our data
@@ -556,6 +560,7 @@ Before returning, a new log is allocated for future samples.  */)
 static Lisp_Object
 export_log (struct profiler_log *plog)
 {
+  if (!plog->log) return Qnil;
   log_t *log = plog->log;
   /* The returned hash table uses `equal' as key equivalence predicate
      which is more discriminating than the `function-equal' used by
@@ -639,7 +644,11 @@ DEFUN ("profiler-memory-log",
 The log is a hash-table mapping backtraces to counters which represent
 the amount of memory allocated at those points.  Every backtrace is a vector
 of functions, where the last few elements may be nil.
-Before returning, a new log is allocated for future samples.  */)
+
+If the profiler has not run since the last invocation of
+`profiler-memory-log' (or was never run at all), return nil.  If the
+profiler is currently running, allocate a new log for future samples
+before returning.  */)
   (void)
 {
   bool prof_mem = profiler_memory_running;