Free dirty_bitmap when unmapping DMA region to fix memory leak

[Hooollin]

The dirty bitmap was allocated when dirty tracking is enabled for a DMA region, but was not released during region teardown, may lead to memory leaks over time.

[jlevon]

Thanks for the fix; please add a test - something like:

jlevon@sent:~/src/libvfio-user$ git diff test/py/test_dirty_pages.py 
diff --git a/test/py/test_dirty_pages.py b/test/py/test_dirty_pages.py
index 6abea1c..8fa35c6 100644
--- a/test/py/test_dirty_pages.py
+++ b/test/py/test_dirty_pages.py
@@ -412,4 +412,15 @@ def test_dirty_pages_uninitialised_dma():
 
     vfu_destroy_ctx(ctx)
 
+
+def test_dirty_pages_ctx_no_stop():
+    test_dirty_pages_setup()
+    vfu_setup_device_migration_callbacks(ctx)
+    start_logging()
+
+    test_dirty_pages_get_modified()
+
+    vfu_destroy_ctx(ctx)
+
+
 # ex: set tabstop=4 shiftwidth=4 softtabstop=4 expandtab:

[Hooollin]

======================================================================================================================= FAILURES =======================================================================================================================
________________________________________________________________________________________________________________ test_shadow_ioeventfd _________________________________________________________________________________________________________________

    def test_shadow_ioeventfd():
        """Configure a shadow ioeventfd, have the client trigger it, confirm that
        the server receives the notification and can see the value."""
    
        # server setup
        ctx = vfu_create_ctx(flags=LIBVFIO_USER_FLAG_ATTACH_NB)
        assert ctx is not None
        ret = vfu_setup_region(ctx, index=VFU_PCI_DEV_BAR0_REGION_IDX, size=0x1000,
                               flags=VFU_REGION_FLAG_RW)
        assert ret == 0
        fo = tempfile.TemporaryFile(dir="/dev/shm")
        fo.truncate(0x1000)
    
        # FIXME
        # Use pip install eventfd?
        #   $ grep EFD_NONBLOCK -wr /usr/include/
        #   /usr/include/bits/eventfd.h:    EFD_NONBLOCK = 00004000
        EFD_NONBLOCK = 0o00004000
    
        efd = eventfd(flags=EFD_NONBLOCK)
        ret = vfu_create_ioeventfd(ctx, VFU_PCI_DEV_BAR0_REGION_IDX, efd, 0x8,
                                   0x16, 0, 0, fo.fileno(), 0x10)
>       assert ret == 0
E       assert -1 == 0

test_shadow_ioeventfd.py:86: AssertionError
----------------------------------------------------------------------------------------------------------------- Captured stdout call -----------------------------------------------------------------------------------------------------------------
DEBUG: shadow ioeventfd not compiled
=============================================================================================================== short test summary info ================================================================================================================
FAILED test_shadow_ioeventfd.py::test_shadow_ioeventfd - assert -1 == 0
============================================================================================================ 1 failed, 223 passed in 4.32s =============================================================================================================
==62607== 
==62607== HEAP SUMMARY:
==62607==     in use at exit: 732,459 bytes in 352 blocks
==62607==   total heap usage: 49,528 allocs, 49,176 frees, 179,602,701 bytes allocated
==62607== 
==62607== 15,166 (14,624 direct, 542 indirect) bytes in 1 blocks are definitely lost in loss record 91 of 96
==62607==    at 0x488C0AC: calloc (in /usr/libexec/valgrind/vgpreload_memcheck-arm64-linux.so)
==62607==    by 0x7BAC6E7: vfu_create_ctx (libvfio-user.c:1905)
==62607==    by 0x7B16623: ??? (in /usr/lib/aarch64-linux-gnu/libffi.so.8.1.4)
==62607==    by 0x7B1383B: ??? (in /usr/lib/aarch64-linux-gnu/libffi.so.8.1.4)
==62607==    by 0x7AE2AB7: ??? (in /usr/lib/python3.12/lib-dynload/_ctypes.cpython-312-aarch64-linux-gnu.so)
==62607==    by 0x7ADF863: ??? (in /usr/lib/python3.12/lib-dynload/_ctypes.cpython-312-aarch64-linux-gnu.so)
==62607==    by 0x4C3F37: _PyObject_MakeTpCall (in /usr/bin/python3.12)
==62607==    by 0x564803: _PyEval_EvalFrameDefault (in /usr/bin/python3.12)
==62607==    by 0x4C5B03: _PyObject_Call_Prepend (in /usr/bin/python3.12)
==62607==    by 0x529DFF: ??? (in /usr/bin/python3.12)
==62607==    by 0x4C3FEF: _PyObject_MakeTpCall (in /usr/bin/python3.12)
==62607==    by 0x564803: _PyEval_EvalFrameDefault (in /usr/bin/python3.12)
==62607== 
==62607== LEAK SUMMARY:
==62607==    definitely lost: 14,624 bytes in 1 blocks
==62607==    indirectly lost: 542 bytes in 3 blocks
==62607==      possibly lost: 0 bytes in 0 blocks
==62607==    still reachable: 717,293 bytes in 348 blocks
==62607==         suppressed: 0 bytes in 0 blocks
==62607== Reachable blocks (those to which a pointer was found) are not shown.
==62607== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==62607== 
==62607== For lists of detected and suppressed errors, rerun with: -s
==62607== ERROR SUMMARY: 1 errors from 1 contexts (suppressed: 0 from 0)

One test case failed, but it appears unrelated to my changes.

[jlevon]

you have some flake8 nits

[Hooollin]

you have some flake8 nits

Just notice that, fixed.

[jlevon]

sorry, flake8 is annoying :)

[Hooollin]

sorry, flake8 is annoying :)

It found another one, just fixed it.

[jlevon]

thanks!