Re: [PATCH v4 6/7] fuzz: add minimization options

[Alexander Bulekov]

On 201229 1240, Qiuhao Li wrote:
> -M1: loop around the remove minimizer
> -M2: try setting bits in operand of write/out to zero
> Signed-off-by: Qiuhao Li <Qiuhao.Li@outlook.com>

Reviewed-by: Alexander Bulekov <alxndr@bu.edu>

> ---
>  scripts/oss-fuzz/minimize_qtest_trace.py | 32 +++++++++++++++++++-----
>  1 file changed, 26 insertions(+), 6 deletions(-)
> 
> diff --git a/scripts/oss-fuzz/minimize_qtest_trace.py 
> b/scripts/oss-fuzz/minimize_qtest_trace.py
> index 70ac0c5366..a681984076 100755
> --- a/scripts/oss-fuzz/minimize_qtest_trace.py
> +++ b/scripts/oss-fuzz/minimize_qtest_trace.py
> @@ -16,6 +16,10 @@ QEMU_PATH = None
>  TIMEOUT = 5
>  CRASH_TOKEN = None
>  
> +# Minimization levels
> +M1 = False # loop around the remove minimizer
> +M2 = False # try setting bits in operand of write/out to zero
> +
>  write_suffix_lookup = {"b": (1, "B"),
>                         "w": (2, "H"),
>                         "l": (4, "L"),
> @@ -23,10 +27,20 @@ write_suffix_lookup = {"b": (1, "B"),
>  
>  def usage():
>      sys.exit("""\
> -Usage: QEMU_PATH="/path/to/qemu" QEMU_ARGS="args" {} input_trace output_trace
> +Usage:
> +
> +QEMU_PATH="/path/to/qemu" QEMU_ARGS="args" {} [Options] input_trace 
> output_trace
> +
>  By default, will try to use the second-to-last line in the output to identify
>  whether the crash occred. Optionally, manually set a string that idenitifes 
> the
>  crash by setting CRASH_TOKEN=
> +
> +Options:
> +
> +-M1: enable a loop around the remove minimizer, which may help decrease some
> +     timing dependant instructions. Off by default.
> +-M2: try setting bits in operand of write/out to zero. Off by default.
> +
>  """.format((sys.argv[0])))
>  
>  deduplication_note = """\n\
> @@ -213,24 +227,30 @@ def minimize_trace(inpath, outpath):
>      print("Setting the timeout for {} seconds".format(TIMEOUT))
>  
>      newtrace = trace[:]
> -
> +    global M1, M2
>      # remove minimizer
>      old_len = len(newtrace) + 1
>      while(old_len > len(newtrace)):
>          old_len = len(newtrace)
> +        print("trace lenth = ", old_len)
>          remove_minimizer(newtrace, outpath)
> +        if not M1 and not M2:
> +            break
>          newtrace = list(filter(lambda s: s != "", newtrace))
>      assert(check_if_trace_crashes(newtrace, outpath))
>  
> -    # set zero minimizer
> -    set_zero_minimizer(newtrace, outpath)
> +    if M2:
> +        set_zero_minimizer(newtrace, outpath)
>      assert(check_if_trace_crashes(newtrace, outpath))
>  
>  
>  if __name__ == '__main__':
>      if len(sys.argv) < 3:
>          usage()
> -
> +    if "-M1" in sys.argv:
> +        M1 = True
> +    if "-M2" in sys.argv:
> +        M2 = True
>      QEMU_PATH = os.getenv("QEMU_PATH")
>      QEMU_ARGS = os.getenv("QEMU_ARGS")
>      if QEMU_PATH is None or QEMU_ARGS is None:
> @@ -239,4 +259,4 @@ if __name__ == '__main__':
>      #     QEMU_ARGS += " -accel qtest"
>      CRASH_TOKEN = os.getenv("CRASH_TOKEN")
>      QEMU_ARGS += " -qtest stdio -monitor none -serial none "
> -    minimize_trace(sys.argv[1], sys.argv[2])
> +    minimize_trace(sys.argv[-2], sys.argv[-1])
> -- 
> 2.25.1
>