Fatal Python error: none_dealloc: deallocating None Python runtime state: finalizing (tstate=0x000055c9bac70920) Current thread 0x00007fbe34e47740 (most recent call first): <no Python frame> Aborted (core dumped) This is caused by a missing Py_INCREF on the returned Py_None, as demonstrated e.g. in https://github.com/mythosil/swig-python-incref or described at https://edcjones.tripod.com/refcount.html ("Remember to INCREF Py_None!") A PoC for triggering this crash is uploaded to https://github.com/z3ntu/pylibfdt-crash . With this patch applied to pylibfdt the crash does not happen. Signed-off-by: Luca Weiss <luca@xxxxxxxxx> --- Unrelated but I've noticed that in this file the indentation is quite mixed between spaces and tabs. This patch tries to keep to the style in the lines around. pylibfdt/libfdt.i | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/pylibfdt/libfdt.i b/pylibfdt/libfdt.i index 075ef70..9ccc57b 100644 --- a/pylibfdt/libfdt.i +++ b/pylibfdt/libfdt.i @@ -1040,14 +1040,16 @@ typedef uint32_t fdt32_t; /* typemap used for fdt_getprop() */ %typemap(out) (const void *) { - if (!$1) + if (!$1) { $result = Py_None; - else + Py_INCREF($result); + } else { %#if PY_VERSION_HEX >= 0x03000000 $result = Py_BuildValue("y#", $1, (Py_ssize_t)*arg4); %#else $result = Py_BuildValue("s#", $1, (Py_ssize_t)*arg4); %#endif + } } /* typemap used for fdt_setprop() */ -- 2.34.1
