commit 77f3f22dd1541c3420d7cc58ab597f8a7a923ef4
author Austin Schuh <austin.linux@gmail.com> Fri Jun 10 16:49:21 2022 -0700
committer Austin Schuh <austin.linux@gmail.com> Sun Jun 19 14:08:24 2022 -0700
tree cccc0df9807aa118a04e8d4f416022c5383c1d31
parent 8e815fbb728ddc4df9714f72beb925cb8c93159d

Make CHECK statements work in realtime code

Factor out the RT -> NRT conversion code from glog back to AOS.  And
call it in the CHECK path so we can CHECK without a secondary crash from
making the CHECK statement.

Change-Id: I0a44770bc1bdf523aacb49b6e6ff89c9c0e20b2f
Signed-off-by: Austin Schuh <austin.linux@gmail.com>

third_party/google-glog/src/logging.cc

diff --git a/third_party/google-glog/src/logging.cc b/third_party/google-glog/src/logging.cc
index db22cd5..a12ea46 100644
--- a/third_party/google-glog/src/logging.cc
+++ b/third_party/google-glog/src/logging.cc
@@ -161,6 +161,16 @@
   return "";
 }
 
+namespace aos {
+void FatalUnsetRealtimePriority() __attribute__((weak));
+}
+
+static void MaybeUnsetRealtime() {
+  if (&aos::FatalUnsetRealtimePriority != nullptr) {
+    aos::FatalUnsetRealtimePriority();
+  }
+}
+
 GLOG_DEFINE_int32(logfile_mode, 0664, "Log file mode/permissions.");
 
 GLOG_DEFINE_string(log_dir, DefaultLogDir(),
@@ -1254,6 +1264,7 @@
       data_ = &fatal_msg_data_shared;
       data_->first_fatal_ = false;
     }
+    MaybeUnsetRealtime();
   }
 
   stream().fill('0');
@@ -1408,6 +1419,11 @@
   static bool already_warned_before_initgoogle = false;
 
   log_mutex.AssertHeld();
+  if (data_->severity_ == GLOG_FATAL && exit_on_dfatal) {
+    if (data_->first_fatal_) {
+      MaybeUnsetRealtime();
+    }
+  }
 
   RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
              data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
@@ -1460,30 +1476,6 @@
   // someone else can use them (as long as they flush afterwards)
   if (data_->severity_ == GLOG_FATAL && exit_on_dfatal) {
     if (data_->first_fatal_) {
-      {
-        // Put this back on SCHED_OTHER by default.
-        DIR *dirp = opendir("/proc/self/task");
-        if (dirp) {
-          struct dirent *directory_entry;
-          while ((directory_entry = readdir(dirp)) != NULL) {
-            int thread_id = std::atoi(directory_entry->d_name);
-
-            // ignore . and .. which are zeroes for some reason
-            if (thread_id != 0) {
-              struct sched_param param;
-              param.sched_priority = 20;
-              sched_setscheduler(thread_id, SCHED_OTHER, &param);
-            }
-          }
-          closedir(dirp);
-        } else {
-          // Can't get other threads; just lower own priority.
-          struct sched_param param;
-          param.sched_priority = 20;
-          sched_setscheduler(0, SCHED_OTHER, &param);
-        }
-      }
-
       // Store crash information so that it is accessible from within signal
       // handlers that may be invoked later.
       RecordCrashReason(&crash_reason);
@@ -2130,8 +2122,10 @@
   return buf;
 }
 
-LogMessageFatal::LogMessageFatal(const char* file, int line) :
-    LogMessage(file, line, GLOG_FATAL) {}
+LogMessageFatal::LogMessageFatal(const char *file, int line)
+    : LogMessage(file, line, GLOG_FATAL) {
+  MaybeUnsetRealtime();
+}
 
 LogMessageFatal::LogMessageFatal(const char* file, int line,
                                  const CheckOpString& result) :
@@ -2144,8 +2138,13 @@
 
 namespace base {
 
+static ostringstream* MakeSafeOstream() {
+  MaybeUnsetRealtime();
+  return new ostringstream;
+}
+
 CheckOpMessageBuilder::CheckOpMessageBuilder(const char *exprtext)
-    : stream_(new ostringstream) {
+    : stream_(MakeSafeOstream()) {
   *stream_ << exprtext << " (";
 }