1 files changed, 158 insertions, 0 deletions
diff --git a/kernel/mm/memcheck.py b/kernel/mm/memcheck.py
new file mode 100644
index 0000000..49f40fd
--- /dev/null
+++ b/kernel/mm/memcheck.py
@@ -0,0 +1,158 @@
+import gdb
+
+import string
+
+import weenix
+import weenix.kmem
+import weenix.stack
+
+
+class SlabAllocation:
+    def __init__(self, addr, stack, allocator, initialization):
+        self.addr = addr
+        self.stack = stack
+        self.allocator = allocator
+        self.initialization = initialization
+
+
+class PageAllocation:
+    def __init__(self, addr, stack, npages, slabdata, initialization):
+        self.addr = addr
+        self.stack = stack
+        self.npages = npages
+        self.slabdata = slabdata
+        self.initialization = initialization
+
+
+class Memcheck:
+    def __init__(self):
+        self._slab_alloc_count = 0
+        self._slab_free_count = 0
+        self._slab_invalid_free = 0
+        self._slab_allocated = {}
+        self._page_alloc_count = 0
+        self._page_free_count = 0
+        self._page_invalid_free = 0
+        self._page_allocated = {}
+        self._initialized = False
+        weenix.Hook("slab_obj_alloc", self._slab_alloc_callback)
+        weenix.Hook("slab_obj_free", self._slab_free_callback)
+        weenix.Hook("page_alloc", self._page_alloc_callback)
+        weenix.Hook("page_free", self._page_free_callback)
+        weenix.Hook("initialized", self._initialized_callback)
+        weenix.Hook("shutdown", self._shutdown_callback)
+
+    def _slab_alloc_callback(self, args):
+        addr = args["addr"]
+        if string.atol(addr, 16) == 0:
+            return False
+        stack = weenix.stack.Stack(gdb.newest_frame().older())
+        allocator = weenix.kmem.SlabAllocator(
+            gdb.Value(string.atol(args["allocator"].split(" ")[0], 16)).cast(
+                gdb.lookup_type("void").pointer()
+            )
+        )
+        self._slab_allocated[addr] = SlabAllocation(
+            addr, stack, allocator, not self._initialized
+        )
+        if self._initialized:
+            self._slab_alloc_count += 1
+        return False
+
+    def _slab_free_callback(self, args):
+        if not args["addr"] in self._slab_allocated:
+            self._slab_invalid_free += 1
+            print("Invalid free of address " + args["addr"] + ":")
+            print(weenix.stack.Stack(gdb.newest_frame().older()))
+        else:
+            if not self._slab_allocated[args["addr"]].initialization:
+                self._slab_free_count += 1
+            del self._slab_allocated[args["addr"]]
+        return False
+
+    def _page_alloc_callback(self, args):
+        addr = args["addr"]
+        if string.atol(addr, 16) == 0:
+            return False
+        stack = weenix.stack.Stack(gdb.newest_frame().older())
+        slabdata = stack.contains("_slab_allocator_grow")
+        self._page_allocated[addr] = PageAllocation(
+            addr, stack, string.atoi(args["npages"]), slabdata, not self._initialized
+        )
+        if self._initialized and not slabdata:
+            self._page_alloc_count += 1
+        return False
+
+    def _page_free_callback(self, args):
+        if not args["addr"] in self._page_allocated:
+            self._page_invalid_free += 1
+            print("Invalid free of address " + args["addr"] + ":")
+            print(weenix.stack.Stack(gdb.newest_frame().older()))
+        elif self._page_allocated[args["addr"]].npages != string.atoi(args["npages"]):
+            self._page_invalid_free += 1
+            print(
+                "Address "
+                + args["addr"]
+                + " allocated for "
+                + str(self._page_allocated[args["addr"]].npages)
+                + " pages:"
+            )
+            print(self._page_allocated[args["addr"]].stack)
+            print("but freed with " + args["npages"] + " pages:")
+            print(weenix.stack.Stack(gdb.newest_frame().older()))
+            del self._page_allocated[args["addr"]]
+        else:
+            if (
+                not self._page_allocated[args["addr"]].initialization
+                and not self._page_allocated[args["addr"]].slabdata
+            ):
+                self._page_free_count += 1
+            del self._page_allocated[args["addr"]]
+        return False
+
+    def _initialized_callback(self, args):
+        self._initialized = True
+        return False
+
+    def _shutdown_callback(self, args):
+        size = 0
+        for alloc in self._slab_allocated.itervalues():
+            if not alloc.initialization:
+                size += alloc.allocator.size()
+                print(
+                    'Leaked {0} bytes from "{1}" at {2}:'.format(
+                        alloc.allocator.size(), alloc.allocator.name(), alloc.addr
+                    )
+                )
+                print(alloc.stack)
+        npages = 0
+        for page in self._page_allocated.itervalues():
+            if not page.initialization and not page.slabdata:
+                npages += page.npages
+                print("Leaked {0} pages at {1}:".format(page.npages, page.addr))
+                print(page.stack)
+        print(
+            "{0} slab allocs, {1} frees ({2} bytes leaked)".format(
+                self._slab_alloc_count, self._slab_free_count, size
+            )
+        )
+        print(
+            "{0} page allocs, {1} frees ({2} pages leaked)".format(
+                self._page_alloc_count, self._page_free_count, npages
+            )
+        )
+        print("{0} invalid slab frees".format(self._slab_invalid_free))
+        print("{0} invalid page frees".format(self._page_invalid_free))
+        return False
+
+
+class MemcheckFlag(weenix.Flag):
+    def __init__(self):
+        weenix.Flag.__init__(self, "memcheck", gdb.COMMAND_DATA)
+
+    def callback(self, value):
+        if value:
+            Memcheck()
+
+
+MemcheckFlag()