chore(gdb): improve resilience against memory corruption and older LVGL versions (#9885)

scripts/gdb/lvglgdb/cmds/dashboard/data_collector.py

@@ -1,22 +1,9 @@
 import base64
-import functools
 from datetime import datetime
 
 import gdb
 
-
-def safe_collect(subsystem: str):
-    """Decorator that wraps a collector function with try/except/warning."""
-    def decorator(fn):
-        @functools.wraps(fn)
-        def wrapper(*args, **kwargs):
-            try:
-                return fn(*args, **kwargs)
-            except Exception as e:
-                gdb.write(f"Warning: failed to collect {subsystem}: {e}\n")
-                return []
-        return wrapper
-    return decorator
+from lvglgdb.lvgl.data_utils import safe_collect
 
 
 # Registry of simple subsystems: (dict_key, lvgl_accessor_method, label)
@@ -39,14 +26,14 @@ def _collect_simple(lvgl, dict_key: str, accessor: str | None, label: str) -> li
     For entries with accessor != None: [x.snapshot().as_dict() for x in lvgl.<accessor>()]
     For entries with accessor == None: [s.as_dict() for s in lvgl.<dict_key>().snapshots()]
     """
-    try:
+
+    @safe_collect(label)
+    def _inner():
         if accessor is not None:
             return [x.snapshot().as_dict() for x in getattr(lvgl, accessor)()]
-        else:
-            return [s.as_dict() for s in getattr(lvgl, dict_key)().snapshots()]
-    except Exception as e:
-        gdb.write(f"Warning: failed to collect {label}: {e}\n")
-        return []
+        return [s.as_dict() for s in getattr(lvgl, dict_key)().snapshots()]
+
+    return _inner()
 
 
 def collect_all() -> dict:
@@ -126,31 +113,24 @@ def _collect_displays(lvgl) -> list:
 @safe_collect("object trees")
 def _collect_object_trees(lvgl) -> list:
     """Collect object trees for all displays with layer name annotations."""
+    from lvglgdb.lvgl.snapshot import Snapshot
+
     result = []
     for disp in lvgl.displays():
-        # Read special layer pointers for name annotation
-        layer_addrs = {}
-        for name in ("bottom_layer", "act_scr", "top_layer", "sys_layer"):
-            try:
-                ptr = disp.super_value(name)
-                if int(ptr):
-                    layer_addrs[int(ptr)] = name
-            except Exception:
-                pass
+        addrs = disp.layer_addrs
 
-        tree = {
-            "display_addr": hex(int(disp)),
-            "screens": [],
-        }
-        for screen in disp.screens:
+        @Snapshot.fallback(layer_name=lambda s: addrs.get(int(s)))
+        def _screen_snapshot(screen):
             snap = screen.snapshot(
-                include_children=True, include_styles=True
+                include_children=True, include_styles=True,
             ).as_dict()
-            # Annotate with layer name if this screen is a known layer
-            screen_addr = int(screen)
-            snap["layer_name"] = layer_addrs.get(screen_addr)
-            tree["screens"].append(snap)
-        result.append(tree)
+            snap["layer_name"] = addrs.get(int(screen))
+            return snap
+
+        result.append({
+            "display_addr": hex(int(disp)),
+            "screens": safe_collect(disp.screens, _screen_snapshot),
+        })
     return result
 
 

scripts/gdb/lvglgdb/lvgl/core/lv_obj.py

@@ -1,3 +1,5 @@
+import gdb
+
 from lvglgdb.value import Value, ValueInput
 from lvglgdb.lvgl.misc.lv_style import LVStyle, decode_selector
 
@@ -99,7 +101,10 @@ class LVObject(Value):
         if not self.spec_attr:
             return
         for i in range(self.child_count):
-            yield LVObject(self.spec_attr.children[i])
+            try:
+                yield LVObject(self.spec_attr.children[i])
+            except Exception:
+                continue
 
     @property
     def obj_styles(self):
@@ -109,17 +114,16 @@ class LVObject(Value):
             return
         styles_arr = self.super_value("styles")
         for i in range(count):
-            raw = styles_arr[i]
-            flags = []
-            if int(raw.is_local):
-                flags.append("local")
-            if int(raw.is_trans):
-                flags.append("trans")
-            if int(raw.is_theme):
-                flags.append("theme")
-            if int(raw.is_disabled):
-                flags.append("disabled")
-            yield ObjStyle(i, int(raw.selector), flags, LVStyle(raw.style))
+            try:
+                raw = styles_arr[i]
+                flags = []
+                raw_val = Value(raw)
+                for flag_name in ("is_local", "is_trans", "is_theme", "is_disabled"):
+                    if raw_val.safe_field(flag_name, False, bool):
+                        flags.append(flag_name.replace("is_", ""))
+                yield ObjStyle(i, int(raw.selector), flags, LVStyle(raw.style))
+            except (gdb.MemoryError, gdb.error):
+                continue
 
     @property
     def styles(self):
@@ -149,14 +153,35 @@ class LVObject(Value):
             "group_addr": self._get_group_addr(),
         }
         if include_children:
-            d["children"] = [
-                c.snapshot(include_children=True, include_styles=include_styles).as_dict()
-                for c in self.children
-            ]
+            d["children"] = self._collect_children(include_styles)
         if include_styles:
-            d["styles"] = [s.snapshot().as_dict() for s in self.obj_styles]
+            d["styles"] = self._collect_styles()
         return Snapshot(d, source=self, display_spec=self._DISPLAY_SPEC)
 
+    def _collect_children(self, include_styles):
+        """Collect child snapshots, substituting corrupted snapshots on error."""
+        from lvglgdb.lvgl.snapshot import Snapshot
+        from lvglgdb.lvgl.data_utils import safe_collect
+
+        @Snapshot.fallback()
+        def _snap(c):
+            return c.snapshot(
+                include_children=True, include_styles=include_styles,
+            ).as_dict()
+
+        return safe_collect(self.children, _snap)
+
+    def _collect_styles(self):
+        """Collect style snapshots, substituting corrupted entries on error."""
+        from lvglgdb.lvgl.snapshot import Snapshot
+        from lvglgdb.lvgl.data_utils import safe_collect
+
+        @Snapshot.fallback()
+        def _snap(s):
+            return s.snapshot().as_dict()
+
+        return safe_collect(self.obj_styles, _snap)
+
     def _get_group_addr(self):
         """Get group address from spec_attr, or None."""
         spec = self.spec_attr
@@ -195,6 +220,9 @@ def dump_obj_styles(obj: ValueInput):
         return [entry["prop_name"], value_str]
 
     for s in styles:
+        if "error" in s:
+            print(f"(corrupted) {s.get('addr', '?')} — {s['error']}")
+            continue
         print(f"[{s['index']}] {s['selector_str']}  {s['flags_str']}")
         print_table(
             s.get("properties", []), ["prop", "value"], _style_row,

scripts/gdb/lvglgdb/lvgl/data_utils.py

@@ -1,4 +1,7 @@
-from typing import Optional
+import functools
+from typing import Callable, Iterable, Optional
+
+import gdb
 
 from lvglgdb.value import Value
 
@@ -16,3 +19,52 @@ def ptr_or_none(val: Value) -> Optional[str]:
     """Convert pointer to hex string or None if NULL."""
     addr = int(val)
     return hex(addr) if addr else None
+
+
+def safe_collect(
+    items_or_label,
+    transform: Callable = None,
+    on_mem_error: Callable = None,
+):
+    """Unified safe collection with two usage modes.
+
+    Iteration mode — collect items, skipping failures:
+        safe_collect(items, transform, on_mem_error=None)
+
+    Decorator mode — wrap an entire collector function:
+        @safe_collect("subsystem name")
+        def collect_xxx(): ...
+
+    In decorator mode, exceptions cause a gdb warning and return [].
+    In iteration mode, gdb.MemoryError/gdb.error calls on_mem_error
+    (or skips), other exceptions skip silently.
+    """
+    if isinstance(items_or_label, str):
+        label = items_or_label
+
+        def decorator(fn):
+            @functools.wraps(fn)
+            def wrapper(*args, **kwargs):
+                try:
+                    return fn(*args, **kwargs)
+                except Exception as e:
+                    import traceback
+                    gdb.write(f"Warning: failed to collect {label}: {e}\n")
+                    traceback.print_exc()
+                    return []
+            return wrapper
+        return decorator
+
+    result = []
+    try:
+        for item in items_or_label:
+            try:
+                result.append(transform(item))
+            except (gdb.MemoryError, gdb.error) as e:
+                if on_mem_error is not None:
+                    result.append(on_mem_error(item, e))
+            except Exception:
+                continue
+    except Exception:
+        pass
+    return result

scripts/gdb/lvglgdb/lvgl/display/lv_display.py

@@ -17,6 +17,8 @@ class LVDisplay(Value):
         "empty_msg": "No displays.",
     }
 
+    _LAYER_NAMES = ("bottom_layer", "act_scr", "top_layer", "sys_layer")
+
     def __init__(self, disp: ValueInput):
         super().__init__(Value.normalize(disp, "lv_display_t"))
 
@@ -36,6 +38,19 @@ class LVDisplay(Value):
         for i in range(self.screen_cnt):
             yield LVObject(screens[i])
 
+    @property
+    def layer_addrs(self) -> dict:
+        """Map screen address -> layer name for known layer pointers."""
+        result = {}
+        for name in self._LAYER_NAMES:
+            try:
+                ptr = self.super_value(name)
+                if int(ptr):
+                    result[int(ptr)] = name
+            except Exception:
+                pass
+        return result
+
     # Buffer-related properties
     @property
     def buf_1(self):

scripts/gdb/lvglgdb/lvgl/draw/lv_draw_unit.py

@@ -23,7 +23,7 @@ class LVDrawUnit(Value):
 
     @property
     def idx(self) -> int:
-        return int(self.super_value("idx"))
+        return self.safe_field("idx", -1, int)
 
     @property
     def next(self):

scripts/gdb/lvglgdb/lvgl/misc/lv_anim.py

@@ -100,11 +100,11 @@ class LVAnim(Value):
 
     @property
     def reverse_duration(self) -> int:
-        return int(self.super_value("reverse_duration"))
+        return self.safe_field("reverse_duration", 0, int)
 
     @property
     def reverse_delay(self) -> int:
-        return int(self.super_value("reverse_delay"))
+        return self.safe_field("reverse_delay", 0, int)
 
     @property
     def repeat_delay(self) -> int:
@@ -116,15 +116,15 @@ class LVAnim(Value):
 
     @property
     def is_paused(self) -> bool:
-        return bool(int(self.super_value("is_paused")))
+        return self.safe_field("is_paused", False, bool)
 
     @property
     def reverse_play_in_progress(self) -> bool:
-        return bool(int(self.super_value("reverse_play_in_progress")))
+        return self.safe_field("reverse_play_in_progress", False, bool)
 
     @property
     def early_apply(self) -> bool:
-        return bool(int(self.super_value("early_apply")))
+        return self.safe_field("early_apply", False, bool)
 
     def _status_str(self) -> str:
         """Short status string for table display."""

scripts/gdb/lvglgdb/lvgl/misc/lv_cache_lru_rb.py

@@ -25,15 +25,26 @@ class LVCacheLRURBIterator(LVCacheIteratorBase):
         return lru_cache, rb_size, ptr_size, rb_node_pp_t, void_pp_t
 
     def _iter_ll_nodes(self, lru_cache, rb_size, ptr_size, rb_node_pp_t, void_pp_t):
-        """Yield (ll_addr, data, back_ptr) for each ll node"""
+        """Yield (ll_addr, data, back_ptr) for each ll node.
+        Skips nodes with inaccessible memory (e.g. corrupted pointers).
+        """
+        inferior = gdb.selected_inferior()
         for ll_node in LVList(lru_cache.ll):
-            ll_addr = int(ll_node)
-            rb_node = Value(ll_node).cast(rb_node_pp_t)
-            data = rb_node.data
-            back_ptr = int(
-                Value(int(data) + rb_size - ptr_size).cast(void_pp_t).dereference()
-            )
-            yield ll_addr, data, back_ptr
+            try:
+                ll_addr = int(ll_node)
+                rb_node = Value(ll_node).cast(rb_node_pp_t)
+                data = rb_node.data
+                data_addr = int(data)
+                if data_addr == 0:
+                    continue
+                # Probe data pointer accessibility before dereferencing
+                inferior.read_memory(data_addr, 1)
+                back_ptr = int(
+                    Value(data_addr + rb_size - ptr_size).cast(void_pp_t).dereference()
+                )
+                yield ll_addr, data, back_ptr
+            except (gdb.MemoryError, gdb.error):
+                continue
 
     def _collect_entries(self):
         """Collect entries from LRU RB cache by traversing the linked list (MRU→LRU order)"""
@@ -46,10 +57,13 @@ class LVCacheLRURBIterator(LVCacheIteratorBase):
             for ll_addr, data, back_ptr in self._iter_ll_nodes(
                 lru_cache, rb_size, ptr_size, rb_node_pp_t, void_pp_t
             ):
-                entry = LVCacheEntry.from_data_ptr(data, self.cache.datatype)
-                entry.extra = Value(back_ptr)
-                entry.ll_addr = ll_addr
-                self._entries.append(entry)
+                try:
+                    entry = LVCacheEntry.from_data_ptr(data, self.cache.datatype)
+                    entry.extra = Value(back_ptr)
+                    entry.ll_addr = ll_addr
+                    self._entries.append(entry)
+                except Exception:
+                    continue
 
         except Exception as e:
             self._collect_error = f"_collect_entries failed: {e}"
@@ -158,7 +172,7 @@ class LVCacheLRURB(LVCache):
         try:
             name = str(self.name)
             return "count" in name.lower() or "lru_rb_count" in str(self.clz).lower()
-        except:
+        except Exception:
             return False
 
     def is_size_based(self):
@@ -166,7 +180,7 @@ class LVCacheLRURB(LVCache):
         try:
             name = str(self.name)
             return "size" in name.lower() or "lru_rb_size" in str(self.clz).lower()
-        except:
+        except Exception:
             return False
 
     def __iter__(self):

scripts/gdb/lvglgdb/lvgl/misc/lv_ll.py

@@ -50,17 +50,23 @@ class LVList(Value):
         nodetype = self.nodetype if self.nodetype else self.lv_ll_node_t
         node = self.current.cast(nodetype)
 
-        self.current = self._next(self.current)
+        try:
+            self.current = self._next(self.current)
+        except (gdb.MemoryError, gdb.error):
+            self.current = None
         return node
 
     @property
     def len(self):
-        len = 0
+        count = 0
         node = self.head
         while node:
-            len += 1
-            node = self._next(node)
-        return len
+            count += 1
+            try:
+                node = self._next(node)
+            except (gdb.MemoryError, gdb.error):
+                break
+        return count
 
     def snapshot(self):
         from lvglgdb.lvgl.snapshot import Snapshot
@@ -72,4 +78,3 @@ class LVList(Value):
             "nodetype": str(self.nodetype) if self.nodetype else None,
         }
         return Snapshot(d, source=self, display_spec=self._DISPLAY_SPEC)
-

scripts/gdb/lvglgdb/lvgl/misc/lv_rb.py

@@ -105,18 +105,26 @@ class LVRedBlackTreeIterator:
         if not self.current:
             raise StopIteration
 
-        data = self.tree.get_data(self.current)
+        try:
+            data = self.tree.get_data(self.current)
+        except (gdb.MemoryError, gdb.error):
+            data = None
 
-        # Move to next node (in-order traversal)
-        if self.current.right:
-            self.current = self.tree.minimum_from(self.current.right)
-        else:
-            parent = self.current.parent
-            while parent and self.current == parent.right:
+        # Advance to next node (in-order traversal)
+        try:
+            if self.current.right:
+                self.current = self.tree.minimum_from(self.current.right)
+            else:
+                parent = self.current.parent
+                while parent and self.current == parent.right:
+                    self.current = parent
+                    parent = parent.parent
                 self.current = parent
-                parent = parent.parent
-            self.current = parent
+        except (gdb.MemoryError, gdb.error):
+            self.current = None
 
+        if data is None:
+            return self.__next__()
         return data
 
     def __str__(self):

scripts/gdb/lvglgdb/lvgl/misc/lv_style.py

@@ -113,12 +113,15 @@ class LVStyle(Value):
                 yield StyleEntry(prop_id, const_props[j].value)
                 j += 1
         elif prop_cnt > 0:
-            # Normal style: values[prop_cnt] then props[prop_cnt] (uint8_t)
+            # Normal style: values[prop_cnt] then props[prop_cnt]
+            # C code: (lv_style_prop_t*)vp + prop_cnt * sizeof(lv_style_value_t)
+            # The pointer arithmetic uses lv_style_prop_t element size as stride.
             base = self.values_and_props
             value_t = gdb.lookup_type("lv_style_value_t")
+            prop_t = gdb.lookup_type("lv_style_prop_t")
             values_ptr = base.cast(value_t, ptr=True)
-            props_offset = prop_cnt * value_t.sizeof
-            props_ptr = Value(int(base) + props_offset).cast("uint8_t", ptr=True)
+            props_offset = prop_cnt * value_t.sizeof * prop_t.sizeof
+            props_ptr = Value(int(base) + props_offset).cast(prop_t, ptr=True)
 
             for j in range(prop_cnt):
                 prop_id = int(props_ptr[j])

scripts/gdb/lvglgdb/lvgl/snapshot.py

@@ -1,4 +1,5 @@
-from typing import Any, Dict, Iterator, Optional
+import functools
+from typing import Any, Callable, Dict, Iterator, Optional
 
 
 class Snapshot:
@@ -7,6 +8,9 @@ class Snapshot:
     Holds a pure Python dict (JSON-serializable), an optional reference
     to the original wrapper (_source), and an optional display spec that
     describes how to format the data for terminal output.
+
+    A snapshot may be marked *corrupted* to indicate that the underlying
+    data could not be fully read (e.g. inaccessible target memory).
     """
 
     __slots__ = ("_data", "_source", "_display_spec")
@@ -17,6 +21,38 @@ class Snapshot:
         self._source = source
         self._display_spec = display_spec
 
+    @classmethod
+    def fallback(cls, addr: Callable = lambda x: int(x), **extra_fns):
+        """Decorator: on exception, return a corrupted snapshot dict.
+
+        Each extra kwarg may be a callable (called with the first arg)
+        or a static value.
+        """
+        def decorator(fn):
+            @functools.wraps(fn)
+            def wrapper(item, *args, **kwargs):
+                try:
+                    return fn(item, *args, **kwargs)
+                except Exception as e:
+                    try:
+                        resolved_addr = hex(addr(item))
+                    except Exception:
+                        resolved_addr = "0x?"
+                    extra = {}
+                    for k, v in extra_fns.items():
+                        try:
+                            extra[k] = v(item) if callable(v) else v
+                        except Exception:
+                            extra[k] = None
+                    d = {"addr": resolved_addr,
+                         "class_name": "(corrupted)",
+                         "error": str(e)}
+                    if extra:
+                        d.update(extra)
+                    return d
+            return wrapper
+        return decorator
+
     # --- dict-like read access ---
 
     def __getitem__(self, key: str) -> Any:

scripts/gdb/lvglgdb/value.py

@@ -38,15 +38,27 @@ class Value(gdb.Value):
             if typ.code == gdb.TYPE_CODE_PTR:
                 target = typ.target().strip_typedefs()
                 if target.code in (gdb.TYPE_CODE_STRUCT, gdb.TYPE_CODE_UNION):
-                    target_type = str(target)
+                    # Prefer .name or .tag over str() to avoid polluted
+                    # anonymous struct expansions like "const struct {...}".
+                    target_type = target.name or target.tag
 
         if target_type is not None:
+            # If val is already a pointer whose target matches target_type,
+            # keep the original type to avoid gdb.lookup_type() which may
+            # resolve to a different compilation unit's definition when
+            # macro-controlled fields cause multiple struct definitions.
+            typ = val.type.strip_typedefs()
+            if typ.code == gdb.TYPE_CODE_PTR:
+                target = typ.target()
+                tname = target.name or target.tag or ""
+                if tname == target_type:
+                    return val
+
             try:
                 gdb.lookup_type(target_type)
             except gdb.error:
                 raise ValueError(f"Type not found: {target_type}")
 
-            typ = val.type.strip_typedefs()
             if typ.code != gdb.TYPE_CODE_PTR:
                 if typ.code in (gdb.TYPE_CODE_INT, gdb.TYPE_CODE_ENUM):
                     val = Value(val.cast(gdb.lookup_type(target_type).pointer()))
@@ -61,11 +73,7 @@ class Value(gdb.Value):
         return val
 
     def __getitem__(self, key):
-        try:
-            value = super().__getitem__(key)
-        except gdb.error:
-            value = super().__getattr__(key)
-        return Value(value)
+        return Value(super().__getitem__(key))
 
     def __getattr__(self, key):
         if hasattr(super(), key):
@@ -88,6 +96,18 @@ class Value(gdb.Value):
     def super_value(self, attr: str) -> "Value":
         return self[attr]
 
+    def safe_field(self, attr: str, default=None, cast=None):
+        """Access a struct field that may not exist in older LVGL versions.
+
+        Returns the field value (optionally converted by *cast*), or
+        *default* when the field is missing.
+        """
+        try:
+            v = Value(gdb.Value.__getitem__(self, attr))
+            return cast(int(v)) if cast is not None else v
+        except (gdb.error, gdb.MemoryError):
+            return default
+
     def as_string(self):
         """Convert to string if possible"""
         try:

scripts/gdb/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "lvglgdb"
-version = "0.4.0"
+version = "0.4.1"
 description = "LVGL GDB scripts"
 readme = "README.md"
 requires-python = ">=3.10"