We spend much time waiting for the timeout program during the minimization process until it passes a time limit. This patch hacks the CLOSED (indicates the redirection file closed) notification in QTest's output if it doesn't crash.
Test with quadrupled trace input at: https://bugs.launchpad.net/qemu/+bug/1890333/comments/1 Original version: real 1m37.246s user 0m13.069s sys 0m8.399s Refined version: real 0m45.904s user 0m16.874s sys 0m10.042s Signed-off-by: Qiuhao Li <qiuhao...@outlook.com> --- scripts/oss-fuzz/minimize_qtest_trace.py | 41 ++++++++++++++++-------- 1 file changed, 28 insertions(+), 13 deletions(-) diff --git a/scripts/oss-fuzz/minimize_qtest_trace.py b/scripts/oss-fuzz/minimize_qtest_trace.py index 5e405a0d5f..aa69c7963e 100755 --- a/scripts/oss-fuzz/minimize_qtest_trace.py +++ b/scripts/oss-fuzz/minimize_qtest_trace.py @@ -29,30 +29,46 @@ whether the crash occred. Optionally, manually set a string that idenitifes the crash by setting CRASH_TOKEN= """.format((sys.argv[0]))) +deduplication_note = """\n\ +Note: While trimming the input, sometimes the mutated trace triggers a different +crash output but indicates the same bug. Under this situation, our minimizer is +incapable of recognizing and stopped from removing it. In the future, we may +use a more sophisticated crash case deduplication method. +\n""" + def check_if_trace_crashes(trace, path): - global CRASH_TOKEN with open(path, "w") as tracefile: tracefile.write("".join(trace)) - rc = subprocess.Popen("timeout -s 9 {timeout}s {qemu_path} {qemu_args} 2>&1\ + proc = subprocess.Popen("timeout {timeout}s {qemu_path} {qemu_args} 2>&1\ < {trace_path}".format(timeout=TIMEOUT, qemu_path=QEMU_PATH, qemu_args=QEMU_ARGS, trace_path=path), shell=True, stdin=subprocess.PIPE, - stdout=subprocess.PIPE) - stdo = rc.communicate()[0] - output = stdo.decode('unicode_escape') - if rc.returncode == 137: # Timed Out - return False - if len(output.splitlines()) < 2: - return False - + stdout=subprocess.PIPE, + encoding="utf-8") + global CRASH_TOKEN if CRASH_TOKEN is None: - CRASH_TOKEN = output.splitlines()[-2] + try: + outs, _ = proc.communicate(timeout=5) + CRASH_TOKEN = outs.splitlines()[-2] + except subprocess.TimeoutExpired: + print("subprocess.TimeoutExpired") + return False + print("Identifying Crashes by this string: {}".format(CRASH_TOKEN)) + global deduplication_note + print(deduplication_note) + return True - return CRASH_TOKEN in output + for line in iter(proc.stdout.readline, b''): + if "CLOSED" in line: + return False + if CRASH_TOKEN in line: + return True + + return False def minimize_trace(inpath, outpath): @@ -66,7 +82,6 @@ def minimize_trace(inpath, outpath): print("Crashed in {} seconds".format(end-start)) TIMEOUT = (end-start)*5 print("Setting the timeout for {} seconds".format(TIMEOUT)) - print("Identifying Crashes by this string: {}".format(CRASH_TOKEN)) i = 0 newtrace = trace[:] -- 2.25.1
