SERVER-45133 Dump mutex info in hang analyzer

1 files changed, 47 insertions, 0 deletions

diff --git a/buildscripts/gdb/mongo.py b/buildscripts/gdb/mongo.py
index b1190231d53..baf0c9c1bbd 100644
--- a/buildscripts/gdb/mongo.py
+++ b/buildscripts/gdb/mongo.py
@@ -1,5 +1,7 @@
 """GDB commands for MongoDB."""
 
+import datetime
+import json
 import os
 import re
 import sys
@@ -15,6 +17,7 @@ try:
     path = os.path.dirname(os.path.dirname(os.path.dirname(printers)))
     sys.path.insert(0, path)
     from libstdcxx.v6 import register_libstdcxx_printers
+    from libstdcxx.v6 import printers as stdlib_printers
     register_libstdcxx_printers(gdb.current_objfile())
     print("Loaded libstdc++ pretty printers from '%s'" % printers)
 except Exception as e:
@@ -349,6 +352,50 @@ class DumpMongoDSessionCatalog(gdb.Command):
 DumpMongoDSessionCatalog()
 
 
+class DumpMongoDBMutexes(gdb.Command):
+    """Print out the state of mutexes in a mongodb (mongod or mongos) process."""
+
+    def __init__(self):
+        """Initialize DumpMongoDBMutexs."""
+        RegisterMongoCommand.register(self, "mongodb-dump-mutexes", gdb.COMMAND_DATA)
+
+    def invoke(self, args, _from_tty):  # pylint: disable=unused-argument,no-self-use,too-many-locals,too-many-branches,too-many-statements
+        """Invoke DumpMongoDBMutexes."""
+
+        print("Dumping mutex info for all Clients")
+
+        service_context = get_global_service_context()
+        client_set = absl_get_nodes(service_context["_clients"])  # pylint: disable=undefined-variable
+        for client_handle in client_set:
+            client = client_handle.dereference().dereference()
+            diagnostic_info_handle = get_decoration(client, "DiagnosticInfo")[1]
+            diagnostic_info_list = diagnostic_info_handle["list"]
+
+            # Use the STL pretty-printer to iterate over the list
+            printer = stdlib_printers.StdForwardListPrinter(
+                str(diagnostic_info_list.type), diagnostic_info_list)
+
+            # Prepare structured output doc
+            client_name = str(client["_desc"])
+            # Chop off the "\"" from the beginning and end of the string
+            client_name = client_name[1:-1]
+            output_doc = {"client": client_name, "waiting": False}
+
+            # This list will only ever have 0 or 1 element in it
+            for _, diag_info in printer.children():
+                output_doc["waiting"] = True
+                output_doc["mutex"] = str(diag_info["_captureName"])[1:-1]
+
+                millis = int(diag_info["_timestamp"]["millis"])
+                dt = datetime.datetime.fromtimestamp(millis / 1000, tz=datetime.timezone.utc)
+                output_doc["since"] = dt.isoformat()
+            print(json.dumps(output_doc))
+
+
+# Register command
+DumpMongoDBMutexes()
+
+
 class MongoDBDumpLocks(gdb.Command):
     """Dump locks in mongod process."""