c9124a1b08
StopInfoBreakpoint keeps a BreakpointLocationCollection for all the breakpoint locations at the BreakpointSite that was hit. It is also lives through the time a given thread is stopped, so there are plenty of opportunities for one of the owning breakpoints to get deleted. But BreakpointLocations don't keep their owner Breakpoints alive, so if the BreakpointLocationCollection can live past when some code gets a chance to delete an owner breakpoint, and then you ask that location for some breakpoint information, it will access freed memory. This wasn't a problem before PR #158128 because the StopInfoBreakpoint just kept the BreakpointSite that was hit, and when you asked it questions, it relooked up that list. That was not great, however, because if you hit breakpoints 5 & 6, deleted 5 and then asked which breakpoints got hit, you would just get 6. For that and other reasons that PR changed to storing a BreakpointLocationCollection of the breakpoints that were hit. That's better from a UI perspective but caused this potential problem. I fix it by adding a variant of the BreakpointLocationCollection that also holds onto a shared pointer to the Breakpoints that own the locations that were hit, thus keeping them alive till the StopInfoBreakpoint goes away. This fixed the ASAN assertion. I also added a test that works harder to cause trouble by deleting breakpoints during a stop.
68 lines
2.7 KiB
Python
68 lines
2.7 KiB
Python
"""
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Make sure that deleting breakpoints in another breakpoint
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callback doesn't cause problems.
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"""
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import lldb
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import lldbsuite.test.lldbutil as lldbutil
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from lldbsuite.test.lldbtest import *
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class TestBreakpointDeletionInCallback(TestBase):
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NO_DEBUG_INFO_TESTCASE = True
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def test_breakpoint_deletion_in_callback(self):
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self.build()
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self.main_source_file = lldb.SBFileSpec("main.c")
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self.delete_others_test()
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def delete_others_test(self):
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"""You might use the test implementation in several ways, say so here."""
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# This function starts a process, "a.out" by default, sets a source
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# breakpoint, runs to it, and returns the thread, process & target.
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# It optionally takes an SBLaunchOption argument if you want to pass
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# arguments or environment variables.
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(target, process, thread, bkpt) = lldbutil.run_to_source_breakpoint(
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self, "Set a breakpoint here", self.main_source_file
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)
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# Now set a breakpoint on "I did something" several times
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#
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bkpt_numbers = []
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for idx in range(0, 5):
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bkpt_numbers.append(
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lldbutil.run_break_set_by_source_regexp(self, "// Deletable location")
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)
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# And add commands to the third one to delete two others:
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deleter = target.FindBreakpointByID(bkpt_numbers[2])
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self.assertTrue(deleter.IsValid(), "Deleter is a good breakpoint")
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commands = lldb.SBStringList()
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deleted_ids = [bkpt_numbers[0], bkpt_numbers[3]]
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for idx in deleted_ids:
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commands.AppendString(f"break delete {idx}")
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deleter.SetCommandLineCommands(commands)
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thread_list = lldbutil.continue_to_breakpoint(process, deleter)
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self.assertEqual(len(thread_list), 1)
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stop_data = thread.stop_reason_data
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# There are 5 breakpoints so 10 break_id, break_loc_id.
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self.assertEqual(len(stop_data), 10)
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# We should have been able to get break ID's and locations for all the
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# breakpoints that we originally hit, but some won't be around anymore:
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for idx in range(0, 5):
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bkpt_id = stop_data[idx * 2]
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print(f"{idx}: {bkpt_id}")
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self.assertIn(bkpt_id, bkpt_numbers, "Found breakpoints are right")
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loc_id = stop_data[idx * 2 + 1]
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self.assertEqual(loc_id, 1, "All breakpoints have one location")
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bkpt = target.FindBreakpointByID(bkpt_id)
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if bkpt_id in deleted_ids:
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# Looking these up should be an error:
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self.assertFalse(bkpt.IsValid(), "Deleted breakpoints are deleted")
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else:
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self.assertTrue(bkpt.IsValid(), "The rest are still valid")
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