4.17-stable review patch. If anyone has any objections, please let me know.
------------------ From: Janne Huttunen <[email protected]> [ Upstream commit db0ba84c04ef2cf293aaada5ae97531127844d9d ] The dictionaries are attached to the parameter tuple that steals the references and takes care of releasing them when appropriate. The code should not decrement the reference counts explicitly. E.g. if libpython has been built with reference debugging enabled, the superfluous DECREFs will trigger this error when running perf script: Fatal Python error: Objects/tupleobject.c:238 object at 0x7f10f2041b40 has negative ref count -1 Aborted (core dumped) If the reference debugging is not enabled, the superfluous DECREFs might cause the dict objects to be silently released while they are still in use. This may trigger various other assertions or just cause perf crashes and/or weird and unexpected data changes in the stored Python objects. Signed-off-by: Janne Huttunen <[email protected]> Acked-by: Jiri Olsa <[email protected]> Acked-by: Namhyung Kim <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Jaroslav Skarvada <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Arnaldo Carvalho de Melo <[email protected]> Signed-off-by: Sasha Levin <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- tools/perf/util/scripting-engines/trace-event-python.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/tools/perf/util/scripting-engines/trace-event-python.c +++ b/tools/perf/util/scripting-engines/trace-event-python.c @@ -676,14 +676,11 @@ static void python_process_tracepoint(st if (_PyTuple_Resize(&t, n) == -1) Py_FatalError("error resizing Python tuple"); - if (!dict) { + if (!dict) call_object(handler, t, handler_name); - } else { + else call_object(handler, t, default_handler_name); - Py_DECREF(dict); - } - Py_XDECREF(all_entries_dict); Py_DECREF(t); } @@ -1003,7 +1000,6 @@ static void python_process_general_event call_object(handler, t, handler_name); - Py_DECREF(dict); Py_DECREF(t); }
