On 201229 1240, Qiuhao Li wrote:
> Simplifying the crash cases by opportunistically setting bits in operands of
> out/write to zero may help to debug, since usually bit one means turn on or
> trigger a function while zero is the default turn-off setting.
>
> Tested Bug 1908062.
>
> Signed-off-by: Qiuhao Li <Qiuhao.Li@outlook.com>
Reviewed-by: Alexander Bulekov <alxndr@bu.edu>
> ---
> scripts/oss-fuzz/minimize_qtest_trace.py | 39 ++++++++++++++++++++++++
> 1 file changed, 39 insertions(+)
>
> diff --git a/scripts/oss-fuzz/minimize_qtest_trace.py b/scripts/oss-fuzz/minimize_qtest_trace.py
> index 378a7ccec6..70ac0c5366 100755
> --- a/scripts/oss-fuzz/minimize_qtest_trace.py
> +++ b/scripts/oss-fuzz/minimize_qtest_trace.py
> @@ -164,6 +164,42 @@ def remove_minimizer(newtrace, outpath):
> i += 1
>
>
> +def set_zero_minimizer(newtrace, outpath):
> + # try setting bits in operands of out/write to zero
> + i = 0
> + while i < len(newtrace):
> + if (not newtrace[i].startswith("write ") and not
> + newtrace[i].startswith("out")):
> + i += 1
> + continue
> + # write ADDR SIZE DATA
> + # outx ADDR VALUE
> + print("\nzero setting bits: {}".format(newtrace[i]))
> +
> + prefix = " ".join(newtrace[i].split()[:-1])
> + data = newtrace[i].split()[-1]
> + data_bin = bin(int(data, 16))
> + data_bin_list = list(data_bin)
> +
> + for j in range(2, len(data_bin_list)):
> + prior = newtrace[i]
> + if (data_bin_list[j] == '1'):
> + data_bin_list[j] = '0'
> + data_try = hex(int("".join(data_bin_list), 2))
> + # It seems qtest only accepts padded hex-values.
> + if len(data_try) % 2 == 1:
> + data_try = data_try[:2] + "0" + data_try[2:-1]
> +
> + newtrace[i] = "{prefix} {data_try}\n".format(
> + prefix=prefix,
> + data_try=data_try)
> +
> + if not check_if_trace_crashes(newtrace, outpath):
> + data_bin_list[j] = '1'
> + newtrace[i] = prior
> + i += 1
> +
> +
> def minimize_trace(inpath, outpath):
> global TIMEOUT
> with open(inpath) as f:
> @@ -184,7 +220,10 @@ def minimize_trace(inpath, outpath):
> old_len = len(newtrace)
> remove_minimizer(newtrace, outpath)
> newtrace = list(filter(lambda s: s != "", newtrace))
> + assert(check_if_trace_crashes(newtrace, outpath))
>
> + # set zero minimizer
> + set_zero_minimizer(newtrace, outpath)
> assert(check_if_trace_crashes(newtrace, outpath))
>
>
> --
> 2.25.1
>