commit c39fee754e453a6ebeac9c254473ce01ec0b8f7a
parent 82ed6edd84ed7174720e69464c6e3898cb9e43ac
Author: Florian Quèze <florian@queze.net>
Date: Thu, 9 Oct 2025 21:56:22 +0000
Bug 1993214 - Show native stacks in resource usage profiles for crash markers, r=ahal,mstange.
Differential Revision: https://phabricator.services.mozilla.com/D267944
Diffstat:
3 files changed, 245 insertions(+), 0 deletions(-)
diff --git a/testing/mozbase/mozcrash/mozcrash/mozcrash.py b/testing/mozbase/mozcrash/mozcrash/mozcrash.py
@@ -44,6 +44,7 @@ StackInfo = namedtuple(
"pid",
"reason",
"java_stack",
+ "crashing_thread_stack",
],
)
@@ -378,6 +379,7 @@ class CrashInfo:
annotations = None
pid = None
process_type = "unknown"
+ crashing_thread_stack = None
if (
self.stackwalk_binary
and os.path.exists(self.stackwalk_binary)
@@ -430,6 +432,7 @@ class CrashInfo:
processed_crash = self._process_json_output(json_output)
signature = processed_crash.get("signature")
pid = processed_crash.get("pid")
+ crashing_thread_stack = processed_crash.get("crashing_thread_stack")
elif not self.stackwalk_binary:
errors.append(
@@ -474,11 +477,13 @@ class CrashInfo:
pid,
reason,
java_stack,
+ crashing_thread_stack,
)
def _process_json_output(self, json_path):
signature = None
pid = None
+ crashing_thread_stack = None
try:
json_file = open(json_path)
@@ -487,6 +492,7 @@ class CrashInfo:
signature = self._generate_signature(crash_json)
pid = crash_json.get("pid")
+ crashing_thread_stack = self._extract_crashing_thread_stack(crash_json)
except Exception as e:
traceback.print_exc()
@@ -495,6 +501,7 @@ class CrashInfo:
return {
"pid": pid,
"signature": signature,
+ "crashing_thread_stack": crashing_thread_stack,
}
def _generate_signature(self, crash_json):
@@ -537,6 +544,65 @@ class CrashInfo:
return signature
+ def _extract_crashing_thread_stack(self, crash_json):
+ """Extract the crashing thread stack as a structured array of frames.
+
+ Returns a list of frame dictionaries with keys:
+ - function: function name (optional)
+ - module: module/library name (optional)
+ - file: source file path (optional)
+ - line: line number (optional)
+ - offset: hex offset for unsymbolicated frames (optional)
+ - inlined: boolean indicating if this is an inlined frame
+ """
+ if not (
+ (crashing_thread := crash_json.get("crashing_thread"))
+ and (frames := crashing_thread.get("frames"))
+ ):
+ return None
+
+ structured_stack = []
+
+ def process_frame(frame, parent_frame=None):
+ """Process a single frame (inline or main) and append to structured_stack.
+
+ Args:
+ frame: Frame data dictionary
+ parent_frame: Parent frame dict (for inline frames to inherit module)
+ """
+ result = {}
+
+ if func := frame.get("function"):
+ result["function"] = func
+ if file_str := frame.get("file"):
+ result["file"] = file_str
+ if line := frame.get("line"):
+ result["line"] = line
+
+ # Inline frames inherit module from parent, main frames have their own
+ if parent_frame:
+ result["inlined"] = True
+ if module := parent_frame.get("module"):
+ result["module"] = module
+ elif module := frame.get("module"):
+ result["module"] = module
+ if module_offset := frame.get("module_offset"):
+ result["module_offset"] = int(module_offset, 16)
+ if function_offset := frame.get("function_offset"):
+ result["function_offset"] = int(function_offset, 16)
+ elif offset := frame.get("offset"):
+ # JIT code or unknown frame - use raw address
+ result["offset"] = int(offset, 16)
+
+ structured_stack.append(result)
+
+ for frame in frames:
+ for inline in frame.get("inlines") or []:
+ process_frame(inline, parent_frame=frame)
+ process_frame(frame)
+
+ return structured_stack if structured_stack else None
+
def _parse_extra_file(self, path):
with open(path) as file:
try:
diff --git a/testing/mozbase/mozlog/mozlog/structuredlog.py b/testing/mozbase/mozlog/mozlog/structuredlog.py
@@ -584,6 +584,7 @@ class StructuredLogger:
Unicode("java_stack", default=None, optional=True),
Unicode("process_type", default=None, optional=True),
List(Unicode, "stackwalk_errors", default=None),
+ List(Any, "crashing_thread_stack", default=None, optional=True),
Unicode("subsuite", default=None, optional=True),
Boolean("quiet", default=False, optional=True),
)
diff --git a/testing/mozbase/mozsystemmonitor/mozsystemmonitor/resourcemonitor.py b/testing/mozbase/mozsystemmonitor/mozsystemmonitor/resourcemonitor.py
@@ -722,6 +722,7 @@ class SystemResourceMonitor:
- "reason": crash reason (optional)
- "test": test name (optional)
- "minidump_path": path to minidump file (optional)
+ - "stack": structured stack (array of frame dicts) (optional)
- "time": timestamp in milliseconds
"""
if not SystemResourceMonitor.instance:
@@ -749,6 +750,10 @@ class SystemResourceMonitor:
minidump_name = os.path.splitext(os.path.basename(minidump_path))[0]
marker_data["minidump"] = minidump_name
+ # Add stack if available (structured format: array of frame dicts)
+ if stack := data.get("crashing_thread_stack"):
+ marker_data["stack"] = stack
+
SystemResourceMonitor.record_event("CRASH", timestamp, marker_data)
@contextmanager
@@ -1392,6 +1397,7 @@ class SystemResourceMonitor:
"endTime": [],
"phase": [],
"category": [],
+ "stack": [],
"length": 0,
},
"stackTable": {
@@ -1459,6 +1465,162 @@ class SystemResourceMonitor:
stringArray.append(string)
return len(stringArray) - 1
+ def get_stack_index(stack_frames):
+ """Get a stack index from a structured stack (array of frame dicts).
+
+ Each frame dict contains:
+ - function: function name (optional)
+ - module: module/library name (optional)
+ - file: source file path (optional)
+ - line: line number (optional)
+ - offset: hex offset for unsymbolicated frames (optional)
+ - inlined: boolean indicating if this is an inlined frame (optional)
+
+ Returns the index of the innermost stack frame, or None if stack_frames is empty.
+ """
+ if not stack_frames:
+ return None
+
+ stackTable = firstThread["stackTable"]
+ frameTable = firstThread["frameTable"]
+ funcTable = firstThread["funcTable"]
+ resourceTable = firstThread["resourceTable"]
+ nativeSymbols = firstThread["nativeSymbols"]
+
+ # Build stack from outermost to innermost
+ stack_index = None
+ inline_depth = 0
+
+ for frame_data in reversed(stack_frames):
+ # Handle inline depth tracking
+ if frame_data.get("inlined"):
+ inline_depth += 1
+ else:
+ inline_depth = 0
+
+ # Get frame components
+ module_name = frame_data.get("module")
+ file_name = frame_data.get("file")
+ line_num = frame_data.get("line")
+
+ # Get offsets - different handling for native vs JIT frames
+ module_offset = frame_data.get("module_offset")
+ function_offset = frame_data.get("function_offset")
+ raw_offset = frame_data.get("offset") # For JIT frames without module
+
+ func_name = frame_data.get("function")
+ if not func_name and (offset := module_offset or raw_offset):
+ func_name = hex(offset)
+
+ # Get or create resource for the module
+ resource_index = -1
+ if module_name:
+ # Find existing resource
+ for i, name_idx in enumerate(resourceTable["name"]):
+ if firstThread["stringArray"][name_idx] == module_name:
+ resource_index = i
+ break
+ else:
+ # Create new resource if not found
+ resource_index = resourceTable["length"]
+ resourceTable["lib"].append(None)
+ resourceTable["name"].append(get_string_index(module_name))
+ resourceTable["host"].append(None)
+ # Possible resourceTypes:
+ # 0 = unknown, 1 = library, 2 = addon, 3 = webhost, 4 = otherhost, 5 = url
+ # https://github.com/firefox-devtools/profiler/blob/32cb6672c7ed47311e9d84963023d51f5147042b/src/profile-logic/data-structures.ts#L322
+ resourceTable["type"].append(1)
+ resourceTable["length"] += 1
+
+ # Create native symbol for unsymbolicated frames
+ # nativeSymbols.address = module_offset - function_offset
+ native_symbol_index = None
+ if (
+ module_offset is not None
+ and function_offset is not None
+ and module_name
+ ):
+ symbol_address = module_offset - function_offset
+
+ # Check if this native symbol already exists
+ for i in range(nativeSymbols["length"]):
+ if (
+ nativeSymbols["libIndex"][i] == resource_index
+ and nativeSymbols["address"][i] == symbol_address
+ ):
+ native_symbol_index = i
+ break
+ else:
+ # Create new native symbol if not found
+ native_symbol_index = nativeSymbols["length"]
+ nativeSymbols["libIndex"].append(resource_index)
+ nativeSymbols["address"].append(symbol_address)
+ nativeSymbols["name"].append(get_string_index(func_name))
+ nativeSymbols["functionSize"].append(None)
+ nativeSymbols["length"] += 1
+
+ # Get or create func index
+ func_name_index = get_string_index(func_name)
+ file_name_index = get_string_index(file_name) if file_name else None
+
+ for i, name_idx in enumerate(funcTable["name"]):
+ if (
+ name_idx == func_name_index
+ and funcTable["resource"][i] == resource_index
+ and funcTable["fileName"][i] == file_name_index
+ and funcTable["lineNumber"][i] == line_num
+ ):
+ func_index = i
+ break
+ else:
+ func_index = funcTable["length"]
+ funcTable["isJS"].append(False)
+ funcTable["relevantForJS"].append(False)
+ funcTable["name"].append(func_name_index)
+ funcTable["resource"].append(resource_index)
+ funcTable["fileName"].append(file_name_index)
+ funcTable["lineNumber"].append(line_num)
+ funcTable["columnNumber"].append(None)
+ funcTable["length"] += 1
+
+ # Get or create frame index
+ # frameTable.address = module_offset for native frames, or offset for JIT frames
+ frame_address = module_offset or raw_offset or -1
+ for i, func_idx in enumerate(frameTable["func"]):
+ if (
+ func_idx == func_index
+ and frameTable["line"][i] == line_num
+ and frameTable["inlineDepth"][i] == inline_depth
+ and frameTable["nativeSymbol"][i] == native_symbol_index
+ and frameTable["address"][i] == frame_address
+ ):
+ frame_index = i
+ break
+ else:
+ frame_index = frameTable["length"]
+ frameTable["address"].append(frame_address)
+ frameTable["inlineDepth"].append(inline_depth)
+ frameTable["category"].append(OTHER_CATEGORY)
+ frameTable["subcategory"].append(0)
+ frameTable["func"].append(func_index)
+ frameTable["nativeSymbol"].append(native_symbol_index)
+ frameTable["innerWindowID"].append(0)
+ frameTable["implementation"].append(None)
+ frameTable["line"].append(line_num)
+ frameTable["column"].append(None)
+ frameTable["length"] += 1
+
+ # Create stack entry
+ new_stack_index = stackTable["length"]
+ stackTable["frame"].append(frame_index)
+ stackTable["prefix"].append(stack_index)
+ stackTable["category"].append(0)
+ stackTable["subcategory"].append(0)
+ stackTable["length"] += 1
+ stack_index = new_stack_index
+
+ return stack_index
+
def add_marker(
name_index, start, end, data, category_index=OTHER_CATEGORY, precision=None
):
@@ -1479,7 +1641,23 @@ class SystemResourceMonitor:
markers["phase"].append(1)
markers["category"].append(category_index)
markers["name"].append(name_index)
+
+ # Extract and process stack if present (structured format: array of frame dicts)
+ stack_index = None
+ if isinstance(data, dict) and "stack" in data:
+ stack = data["stack"]
+ if isinstance(stack, list):
+ stack_index = get_stack_index(stack)
+ del data["stack"]
+ # Add cause object to marker data for processed profile format
+ if stack_index is not None:
+ data["cause"] = {
+ "time": markers["startTime"][-1],
+ "stack": stack_index,
+ }
+
markers["data"].append(data)
+ markers["stack"].append(stack_index)
markers["length"] = markers["length"] + 1
def format_percent(value):
