forked from Imagelibrary/binutils-gdb
802c2244af
Re-running 'isort' (via pre-commit) showed that the file py-read-memory-leak.py (from the gdb test suite) needed a small patch.
94 lines
3.3 KiB
Python
94 lines
3.3 KiB
Python
# Copyright (C) 2024 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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import os
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import tracemalloc
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import gdb
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# A global variable in which we store a reference to the memory buffer
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# returned from gdb.Inferior.read_memory().
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mem_buf = None
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# A global filters list, we only care about memory allocations
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# originating from this script.
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filters = [tracemalloc.Filter(True, "*" + os.path.basename(__file__))]
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# Run the test. When CLEAR is True we clear the global INF variable
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# before comparing the before and after memory allocation traces.
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# When CLEAR is False we leave INF set to reference the gdb.Inferior
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# object, thus preventing the gdb.Inferior from being deallocated.
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def test(clear):
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global filters, mem_buf
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addr = gdb.parse_and_eval("px")
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inf = gdb.inferiors()[0]
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# Start tracing, and take a snapshot of the current allocations.
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tracemalloc.start()
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snapshot1 = tracemalloc.take_snapshot()
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# Read from the inferior, this allocate a memory buffer object.
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mem_buf = inf.read_memory(addr, 4096)
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# Possibly clear the global INF variable.
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if clear:
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mem_buf = None
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# Now grab a second snapshot of memory allocations, and stop
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# tracing memory allocations.
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snapshot2 = tracemalloc.take_snapshot()
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tracemalloc.stop()
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# Filter the snapshots; we only care about allocations originating
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# from this file.
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snapshot1 = snapshot1.filter_traces(filters)
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snapshot2 = snapshot2.filter_traces(filters)
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# Compare the snapshots, this leaves only things that were
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# allocated, but not deallocated since the first snapshot.
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stats = snapshot2.compare_to(snapshot1, "traceback")
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# Total up all the allocated things.
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total = 0
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for stat in stats:
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total += stat.size_diff
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return total
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# The first time we run this some global state will be allocated which
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# shows up as memory that is allocated, but not released. So, run the
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# test once and discard the result.
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test(True)
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# Now run the test twice, the first time we clear our global reference
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# to the memory buffer object, which should allow Python to deallocate
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# the object. The second time we hold onto the global reference,
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# preventing Python from performing the deallocation.
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bytes_with_clear = test(True)
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bytes_without_clear = test(False)
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# The bug that used to exist in GDB was that even when we released the
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# global reference the gdb.Inferior object would not be deallocated.
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if bytes_with_clear > 0:
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raise gdb.GdbError("memory leak when memory buffer should be released")
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if bytes_without_clear == 0:
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raise gdb.GdbError("memory buffer object is no longer allocated")
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# Print a PASS message that the test script can see.
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print("PASS")
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