371d1a8e3e
DynamicLoaderWindowsDYLD uses pointers to Modules to maintain a map from modules to their addresses, but it does not need to keep "strong" references to them. Weak pointers should be enough, and would allow modules to be released elsewhere. Other DynamicLoader classes do not use shared pointers as well. For example, DynamicLoaderPOSIXDYLD has a similar map with weak pointers. Actually testing for modules being completely released can be tricky. The test here is just to illustrate the case where shared pointers kept modules in DynamicLoaderWindowsDYLD and prevented them from being released. The test executes the following sequence: 1. Create a target, load an executable and run it. 2. Remove one module from the target. The target should be the last actual use of the module, but we have another reference to it in the shared module cache. 3. Call MemoryPressureDetected to remove this last reference from the cache. 4. Replace the corresponding DLL file. LLDB memory maps DLLs, and this makes files read-only on Windows. Unless the modules are completely released (and therefore unmapped), (4) is going to fail with "access denied". However, the test does not trigger the bug completely - it passes with and without the change.
63 lines
1.7 KiB
Python
63 lines
1.7 KiB
Python
import lldb
|
|
from lldbsuite.test.decorators import *
|
|
from lldbsuite.test.lldbtest import *
|
|
from lldbsuite.test import lldbutil
|
|
|
|
import gc
|
|
import os
|
|
|
|
|
|
class ReplaceDllTestCase(TestBase):
|
|
@skipUnlessWindows
|
|
def test(self):
|
|
"""
|
|
Test that LLDB unlocks module files once all references are released.
|
|
"""
|
|
|
|
exe = self.getBuildArtifact("a.out")
|
|
foo = self.getBuildArtifact("foo.dll")
|
|
bar = self.getBuildArtifact("bar.dll")
|
|
|
|
self.build(
|
|
dictionary={
|
|
"DYLIB_NAME": "foo",
|
|
"DYLIB_C_SOURCES": "foo.c",
|
|
"C_SOURCES": "test.c",
|
|
}
|
|
)
|
|
self.build(
|
|
dictionary={
|
|
"DYLIB_ONLY": "YES",
|
|
"DYLIB_NAME": "bar",
|
|
"DYLIB_C_SOURCES": "bar.c",
|
|
}
|
|
)
|
|
|
|
target = self.dbg.CreateTarget(exe)
|
|
self.assertTrue(target, VALID_TARGET)
|
|
|
|
shlib_names = ["foo"]
|
|
environment = self.registerSharedLibrariesWithTarget(target, shlib_names)
|
|
process = target.LaunchSimple(
|
|
None, environment, self.get_process_working_directory()
|
|
)
|
|
self.assertEqual(process.GetExitStatus(), 42)
|
|
|
|
module = next((m for m in target.modules if "foo" in m.file.basename), None)
|
|
self.assertIsNotNone(module)
|
|
self.assertEqual(module.file.fullpath, foo)
|
|
|
|
target.RemoveModule(module)
|
|
del module
|
|
gc.collect()
|
|
|
|
self.dbg.MemoryPressureDetected()
|
|
|
|
os.remove(foo)
|
|
os.rename(bar, foo)
|
|
|
|
process = target.LaunchSimple(
|
|
None, environment, self.get_process_working_directory()
|
|
)
|
|
self.assertEqual(process.GetExitStatus(), 43)
|