fix(profiling): serialisable stack key

Ensure that the stack key used to group events is actually hashable.

ddtrace/profiling/exporter/pprof.pyx

@@ -13,6 +13,7 @@ from ddtrace.internal import packages
 from ddtrace.internal._encoding import ListStringTable as _StringTable
 from ddtrace.internal.compat import ensure_text
 from ddtrace.internal.datadog.profiling.ddup.utils import sanitize_string
+from ddtrace.internal.logger import get_logger
 from ddtrace.internal.utils import config
 from ddtrace.profiling import event
 from ddtrace.profiling import exporter
@@ -23,6 +24,9 @@ from ddtrace.profiling.collector import stack_event
 from ddtrace.profiling.collector import threading
 
 
+log = get_logger(__name__)
+
+
 if hasattr(typing, "TypedDict"):
     Package = typing.TypedDict(
         "Package",
@@ -129,7 +133,10 @@ cdef groupby(object collection, object key):
     cdef dict groups = {}
 
     for item in collection:
-        groups.setdefault(key(item), []).append(item)
+        try:
+            groups.setdefault(key(item), []).append(item)
+        except Exception:
+            log.warning("Failed to group item %r", item, exc_info=True)
 
     return groups.items()
 

releasenotes/notes/fix-profiling-stack-event-data-dc50c8e7663718cc.yaml

@@ -0,0 +1,5 @@
+---
+fixes:
+  - |
+    profiling: handle unexpected stack data to prevent the profiler from
+    stopping.