Enhancement on Deterministic stage (#1972)

* fuzzer: init commit based on aflpp 60dc37a8cf09f8e9048e4b6a2204d6c90b27655a

* fuzzers: adding the skip variables and initialize

* log: profile the det/havoc finding

* log: add profile log output

* fuzzers: sperate log/skipdet module

* fuzzers: add quick eff_map calc

* fuzzers: add skip_eff_map in fuzz_one

* fuzzers: mark whole input space in eff_map

* fuzzers: add undet bit threshold to skip some seeds

* fuzzers: fix one byte overflow

* fuzzers: fix overflow

* fix code format

* add havoc only again

* code format

* remove log to INTROSPECTION, rename skipdet module

* rename skipdet module

* remove log to stats

* clean redundant code

* code format

* remove redundant code format check

* remove redundant doc

* remove redundant objects

* clean files

* change -d to default skipdet

* disable deterministic when using CUSTOM_MUTATOR

* revert fix

10 files changed, 680 insertions, 49 deletions

diff --git a/include/afl-fuzz.h b/include/afl-fuzz.h
index f1813df6..c2b09b2e 100644
--- a/include/afl-fuzz.h
+++ b/include/afl-fuzz.h
@@ -149,6 +149,48 @@ struct tainted {
 
 };
 
+struct inf_profile {
+
+  u32 inf_skipped_bytes;               /* Inference Stage Profiling         */
+  u64 inf_execs_cost, inf_time_cost;
+
+};
+
+/* ToDo: add cmplog profile as well */
+struct havoc_profile {
+
+  u32 queued_det_stage,                 /* Det/Havoc Stage Profiling        */
+      queued_havoc_stage, total_queued_det, edge_det_stage, edge_havoc_stage,
+      total_det_edge;
+
+  u64 det_stage_time, havoc_stage_time, total_det_time;
+
+};
+
+struct skipdet_entry {
+
+  u8  continue_inf, done_eff;
+  u32 undet_bits, quick_eff_bytes;
+
+  u8 *skip_eff_map,                     /* we'v finish the eff_map          */
+      *done_inf_map;                    /* some bytes are not done yet      */
+
+};
+
+struct skipdet_global {
+
+  u8 use_skip_havoc;
+
+  u32 undet_bits_threshold;
+
+  u64 last_cov_undet;
+
+  u8 *virgin_det_bits;                  /* global fuzzed bits               */
+
+  struct inf_profile *inf_prof;
+
+};
+
 struct queue_entry {
 
   u8 *fname;                            /* File name for the test case      */
@@ -203,6 +245,8 @@ struct queue_entry {
 
   struct queue_entry *mother;           /* queue entry this based on        */
 
+  struct skipdet_entry *skipdet_e;
+
 };
 
 struct extra_data {
@@ -247,6 +291,8 @@ enum {
   /* 19 */ STAGE_CUSTOM_MUTATOR,
   /* 20 */ STAGE_COLORIZATION,
   /* 21 */ STAGE_ITS,
+  /* 22 */ STAGE_INF,
+  /* 23 */ STAGE_QUICK,
 
   STAGE_NUM_MAX
 
@@ -782,6 +828,11 @@ typedef struct afl_state {
    * is too large) */
   struct queue_entry **q_testcase_cache;
 
+  /* Global Profile Data for deterministic/havoc-splice stage */
+  struct havoc_profile *havoc_prof;
+
+  struct skipdet_global *skipdet_g;
+
 #ifdef INTROSPECTION
   char  mutation[8072];
   char  m_tmp[4096];
@@ -1232,6 +1283,13 @@ AFL_RAND_RETURN rand_next(afl_state_t *afl);
 /* probability between 0.0 and 1.0 */
 double rand_next_percent(afl_state_t *afl);
 
+/* SkipDet Functions */
+
+u8 skip_deterministic_stage(afl_state_t *, u8 *, u8 *, u32, u64);
+u8 is_det_timeout(u64, u8);
+
+void plot_profile_data(afl_state_t *, struct queue_entry *);
+
 /**** Inline routines ****/
 
 /* Generate a random number (from 0 to limit - 1). This may
diff --git a/include/config.h b/include/config.h
index 63340650..7ad73c2f 100644
--- a/include/config.h
+++ b/include/config.h
@@ -52,6 +52,18 @@
 /* Default file permission umode when creating files (default: 0600) */
 #define DEFAULT_PERMISSION 0600
 
+/* SkipDet's global configuration */
+
+#define MINIMAL_BLOCK_SIZE 64
+#define SMALL_DET_TIME (60 * 1000 * 1000U)
+#define MAXIMUM_INF_EXECS (16 * 1024U)
+#define MAXIMUM_QUICK_EFF_EXECS (64 * 1024U)
+#define THRESHOLD_DEC_TIME (20 * 60 * 1000U)
+
+/* Set the Prob of selecting eff_bytes 3 times more than original,
+   Now disabled */
+#define EFF_HAVOC_RATE 3
+
 /* CMPLOG/REDQUEEN TUNING
  *
  * Here you can modify tuning and solving options for CMPLOG.
diff --git a/include/forkserver.h b/include/forkserver.h
index f6230fe8..f1d3b5b1 100644
--- a/include/forkserver.h
+++ b/include/forkserver.h
@@ -126,7 +126,8 @@ typedef struct afl_forkserver {
   u8 *out_file,                         /* File to fuzz, if any             */
       *target_path;                     /* Path of the target               */
 
-  FILE *plot_file;                      /* Gnuplot output file              */
+  FILE *plot_file,                      /* Gnuplot output file              */
+      *det_plot_file;
 
   /* Note: last_run_timed_out is u32 to send it to the child as 4 byte array */
   u32 last_run_timed_out;               /* Traced process timed out?        */
diff --git a/src/afl-fuzz-init.c b/src/afl-fuzz-init.c
index 8ab44a3b..057d8cf5 100644
--- a/src/afl-fuzz-init.c
+++ b/src/afl-fuzz-init.c
@@ -2236,6 +2236,21 @@ void setup_dirs_fds(afl_state_t *afl) {
 
   fflush(afl->fsrv.plot_file);
 
+#ifdef INTROSPECTION
+
+  tmp = alloc_printf("%s/plot_det_data", afl->out_dir);
+
+  int fd = open(tmp, O_WRONLY | O_CREAT, DEFAULT_PERMISSION);
+  if (fd < 0) { PFATAL("Unable to create '%s'", tmp); }
+  ck_free(tmp);
+
+  afl->fsrv.det_plot_file = fdopen(fd, "w");
+  if (!afl->fsrv.det_plot_file) { PFATAL("fdopen() failed"); }
+
+  if (afl->in_place_resume) { fseek(afl->fsrv.det_plot_file, 0, SEEK_END); }
+
+#endif
+
   /* ignore errors */
 
 }
diff --git a/src/afl-fuzz-one.c b/src/afl-fuzz-one.c
index 01e34b69..4a7d3fad 100644
--- a/src/afl-fuzz-one.c
+++ b/src/afl-fuzz-one.c
@@ -545,12 +545,37 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
   }
 
+  u64 before_det_time = get_cur_time();
+#ifdef INTROSPECTION
+
+  u64 before_havoc_time;
+  u32 before_det_findings = afl->queued_items,
+      before_det_edges = count_non_255_bytes(afl, afl->virgin_bits),
+      before_havoc_findings, before_havoc_edges;
+  u8 is_logged = 0;
+
+#endif
+  if (!afl->skip_deterministic) {
+
+    if (!skip_deterministic_stage(afl, in_buf, out_buf, len, before_det_time)) {
+
+      goto abandon_entry;
+
+    }
+
+  }
+
+  u8 *skip_eff_map = afl->queue_cur->skipdet_e->skip_eff_map;
+
   /* Skip right away if -d is given, if it has not been chosen sufficiently
      often to warrant the expensive deterministic stage (fuzz_level), or
      if it has gone through deterministic testing in earlier, resumed runs
      (passed_det). */
+  /* if skipdet decide to skip the seed or no interesting bytes found,
+     we skip the whole deterministic stage as well */
 
   if (likely(afl->skip_deterministic) || likely(afl->queue_cur->passed_det) ||
+      likely(!afl->queue_cur->skipdet_e->quick_eff_bytes) ||
       likely(perf_score <
              (afl->queue_cur->depth * 30 <= afl->havoc_max_mult * 100
                   ? afl->queue_cur->depth * 30
@@ -609,6 +634,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur >> 3;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     FLIP_BIT(out_buf, afl->stage_cur);
 
 #ifdef INTROSPECTION
@@ -725,6 +754,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur >> 3;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     FLIP_BIT(out_buf, afl->stage_cur);
     FLIP_BIT(out_buf, afl->stage_cur + 1);
 
@@ -760,6 +793,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur >> 3;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     FLIP_BIT(out_buf, afl->stage_cur);
     FLIP_BIT(out_buf, afl->stage_cur + 1);
     FLIP_BIT(out_buf, afl->stage_cur + 2);
@@ -828,6 +865,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     out_buf[afl->stage_cur] ^= 0xFF;
 
 #ifdef INTROSPECTION
@@ -837,37 +878,6 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     if (common_fuzz_stuff(afl, out_buf, len)) { goto abandon_entry; }
 
-    /* We also use this stage to pull off a simple trick: we identify
-       bytes that seem to have no effect on the current execution path
-       even when fully flipped - and we skip them during more expensive
-       deterministic stages, such as arithmetics or known ints. */
-
-    if (!eff_map[EFF_APOS(afl->stage_cur)]) {
-
-      u64 cksum;
-
-      /* If in non-instrumented mode or if the file is very short, just flag
-         everything without wasting time on checksums. */
-
-      if (!afl->non_instrumented_mode && len >= EFF_MIN_LEN) {
-
-        cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
-
-      } else {
-
-        cksum = ~prev_cksum;
-
-      }
-
-      if (cksum != prev_cksum) {
-
-        eff_map[EFF_APOS(afl->stage_cur)] = 1;
-        ++eff_cnt;
-
-      }
-
-    }
-
     out_buf[afl->stage_cur] ^= 0xFF;
 
   }
@@ -876,18 +886,8 @@ u8 fuzz_one_original(afl_state_t *afl) {
      whole thing as worth fuzzing, since we wouldn't be saving much time
      anyway. */
 
-  if (eff_cnt != (u32)EFF_ALEN(len) &&
-      eff_cnt * 100 / EFF_ALEN(len) > EFF_MAX_PERC) {
-
-    memset(eff_map, 1, EFF_ALEN(len));
-
-    afl->blocks_eff_select += EFF_ALEN(len);
-
-  } else {
-
-    afl->blocks_eff_select += eff_cnt;
-
-  }
+  memset(eff_map, 1, EFF_ALEN(len));
+  afl->blocks_eff_select += EFF_ALEN(len);
 
   afl->blocks_eff_total += EFF_ALEN(len);
 
@@ -921,6 +921,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     *(u16 *)(out_buf + i) ^= 0xFFFF;
@@ -967,6 +971,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     *(u32 *)(out_buf + i) ^= 0xFFFFFFFF;
@@ -1023,6 +1031,10 @@ skip_bitflip:
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 1; j <= ARITH_MAX; ++j) {
@@ -1110,6 +1122,10 @@ skip_bitflip:
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 1; j <= ARITH_MAX; ++j) {
@@ -1244,6 +1260,10 @@ skip_bitflip:
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 1; j <= ARITH_MAX; ++j) {
@@ -1381,6 +1401,10 @@ skip_arith:
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < (u32)sizeof(interesting_8); ++j) {
@@ -1444,6 +1468,10 @@ skip_arith:
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < sizeof(interesting_16) / 2; ++j) {
@@ -1536,6 +1564,10 @@ skip_arith:
 
     }
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < sizeof(interesting_32) / 4; ++j) {
@@ -1626,6 +1658,10 @@ skip_interest:
 
     u32 last_len = 0;
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     /* Extras are sorted by size, from smallest to largest. This means
@@ -1693,6 +1729,10 @@ skip_interest:
 
   for (i = 0; i <= (u32)len; ++i) {
 
+    if (!skip_eff_map[i % len]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < afl->extras_cnt; ++j) {
@@ -1755,6 +1795,10 @@ skip_user_extras:
 
     u32 last_len = 0;
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     u32 min_extra_len = MIN(afl->a_extras_cnt, (u32)USE_AUTO_EXTRAS);
@@ -1813,6 +1857,10 @@ skip_user_extras:
 
   for (i = 0; i <= (u32)len; ++i) {
 
+    if (!skip_eff_map[i % len]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < afl->a_extras_cnt; ++j) {
@@ -2020,6 +2068,19 @@ custom_mutator_stage:
 
 havoc_stage:
 
+#ifdef INTROSPECTION
+
+  if (!is_logged) {
+
+    is_logged = 1;
+    before_havoc_findings = afl->queued_items;
+    before_havoc_edges = count_non_255_bytes(afl, afl->virgin_bits);
+    before_havoc_time = get_cur_time();
+
+  }
+
+#endif
+
   if (unlikely(afl->custom_only)) {
 
     /* Force UI update */
@@ -3430,6 +3491,25 @@ retry_splicing:
 
   ret_val = 0;
 
+#ifdef INTROSPECTION
+
+  afl->havoc_prof->queued_det_stage =
+      before_havoc_findings - before_det_findings;
+  afl->havoc_prof->queued_havoc_stage =
+      afl->queued_items - before_havoc_findings;
+  afl->havoc_prof->total_queued_det += afl->havoc_prof->queued_det_stage;
+  afl->havoc_prof->edge_det_stage = before_havoc_edges - before_det_edges;
+  afl->havoc_prof->edge_havoc_stage =
+      count_non_255_bytes(afl, afl->virgin_bits) - before_havoc_edges;
+  afl->havoc_prof->total_det_edge += afl->havoc_prof->edge_det_stage;
+  afl->havoc_prof->det_stage_time = before_havoc_time - before_det_time;
+  afl->havoc_prof->havoc_stage_time = get_cur_time() - before_havoc_time;
+  afl->havoc_prof->total_det_time += afl->havoc_prof->det_stage_time;
+
+  plot_profile_data(afl, afl->queue_cur);
+
+#endif
+
 /* we are through with this queue entry - for this iteration */
 abandon_entry:
 
diff --git a/src/afl-fuzz-queue.c b/src/afl-fuzz-queue.c
index 4b9627f7..67931bba 100644
--- a/src/afl-fuzz-queue.c
+++ b/src/afl-fuzz-queue.c
@@ -664,6 +664,8 @@ void add_to_queue(afl_state_t *afl, u8 *fname, u32 len, u8 passed_det) {
 
   }
 
+  q->skipdet_e = (struct skipdet_entry *)ck_alloc(sizeof(struct skipdet_entry));
+
 }
 
 /* Destroy the entire queue. */
@@ -679,6 +681,15 @@ void destroy_queue(afl_state_t *afl) {
     q = afl->queue_buf[i];
     ck_free(q->fname);
     ck_free(q->trace_mini);
+    if (q->skipdet_e) {
+
+      if (q->skipdet_e->done_inf_map) ck_free(q->skipdet_e->done_inf_map);
+      if (q->skipdet_e->skip_eff_map) ck_free(q->skipdet_e->skip_eff_map);
+
+      ck_free(q->skipdet_e);
+
+    }
+
     ck_free(q);
 
   }
diff --git a/src/afl-fuzz-skipdet.c b/src/afl-fuzz-skipdet.c
new file mode 100644
index 00000000..e52d59a3
--- /dev/null
+++ b/src/afl-fuzz-skipdet.c
@@ -0,0 +1,403 @@
+
+
+#include "afl-fuzz.h"
+
+void flip_range(u8 *input, u32 pos, u32 size) {
+
+  for (u32 i = 0; i < size; i++)
+    input[pos + i] ^= 0xFF;
+
+  return;
+
+}
+
+#define MAX_EFF_TIMEOUT (10 * 60 * 1000)
+#define MAX_DET_TIMEOUT (15 * 60 * 1000)
+u8 is_det_timeout(u64 cur_ms, u8 is_flip) {
+
+  if (is_flip) {
+
+    if (unlikely(get_cur_time() - cur_ms > MAX_EFF_TIMEOUT)) return 1;
+
+  } else {
+
+    if (unlikely(get_cur_time() - cur_ms > MAX_DET_TIMEOUT)) return 1;
+
+  }
+
+  return 0;
+
+}
+
+/* decide if the seed should be deterministically fuzzed */
+
+u8 should_det_fuzz(afl_state_t *afl, struct queue_entry *q) {
+
+  if (!afl->skipdet_g->virgin_det_bits) {
+
+    afl->skipdet_g->virgin_det_bits =
+        (u8 *)ck_alloc(sizeof(u8) * afl->fsrv.map_size);
+
+  }
+
+  if (!q->favored || q->passed_det) return 0;
+  if (!q->trace_mini) return 0;
+
+  if (!afl->skipdet_g->last_cov_undet)
+    afl->skipdet_g->last_cov_undet = get_cur_time();
+
+  if (get_cur_time() - afl->skipdet_g->last_cov_undet >= THRESHOLD_DEC_TIME) {
+
+    if (afl->skipdet_g->undet_bits_threshold >= 2) {
+
+      afl->skipdet_g->undet_bits_threshold *= 0.75;
+      afl->skipdet_g->last_cov_undet = get_cur_time();
+
+    }
+
+  }
+
+  u32 new_det_bits = 0;
+
+  for (u32 i = 0; i < afl->fsrv.map_size; i++) {
+
+    if (unlikely(q->trace_mini[i >> 3] & (1 << (i & 7)))) {
+
+      if (!afl->skipdet_g->virgin_det_bits[i]) { new_det_bits++; }
+
+    }
+
+  }
+
+  if (!afl->skipdet_g->undet_bits_threshold)
+    afl->skipdet_g->undet_bits_threshold = new_det_bits * 0.05;
+
+  if (new_det_bits >= afl->skipdet_g->undet_bits_threshold) {
+
+    afl->skipdet_g->last_cov_undet = get_cur_time();
+    q->skipdet_e->undet_bits = new_det_bits;
+
+    for (u32 i = 0; i < afl->fsrv.map_size; i++) {
+
+      if (unlikely(q->trace_mini[i >> 3] & (1 << (i & 7)))) {
+
+        if (!afl->skipdet_g->virgin_det_bits[i])
+          afl->skipdet_g->virgin_det_bits[i] = 1;
+
+      }
+
+    }
+
+    return 1;
+
+  }
+
+  return 0;
+
+}
+
+/*
+  consists of two stages that
+  return 0 if exec failed.
+*/
+
+u8 skip_deterministic_stage(afl_state_t *afl, u8 *orig_buf, u8 *out_buf,
+                            u32 len, u64 before_det_time) {
+
+  u64 orig_hit_cnt, new_hit_cnt;
+
+  if (afl->queue_cur->skipdet_e->done_eff) return 1;
+
+  if (!should_det_fuzz(afl, afl->queue_cur)) return 1;
+
+  /* Add check to make sure that for seeds without too much undet bits,
+     we ignore them */
+
+  /******************
+   * SKIP INFERENCE *
+   ******************/
+
+  afl->stage_short = "inf";
+  afl->stage_name = "inference";
+  afl->stage_cur = 0;
+  orig_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  u8 *inf_eff_map = (u8 *)ck_alloc(sizeof(u8) * len);
+  memset(inf_eff_map, 1, sizeof(u8) * len);
+
+  if (common_fuzz_stuff(afl, orig_buf, len)) { return 0; }
+
+  u64 prev_cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+  u64 _prev_cksum = prev_cksum;
+
+  if (MINIMAL_BLOCK_SIZE * 8 < len) {
+
+    // u64 size_skiped = 0, quick_skip_exec = total_execs, quick_skip_time =
+    // get_cur_time();
+    u64 pre_inf_exec = afl->fsrv.total_execs, pre_inf_time = get_cur_time();
+
+    /* if determine stage time / input size is too small, just go ahead */
+
+    u32 pos = 0, cur_block_size = MINIMAL_BLOCK_SIZE, max_block_size = len / 8;
+
+    while (pos < len - 1) {
+
+      cur_block_size = MINIMAL_BLOCK_SIZE;
+
+      while (cur_block_size < max_block_size) {
+
+        u32 flip_block_size =
+            (cur_block_size + pos < len) ? cur_block_size : len - 1 - pos;
+
+        afl->stage_cur += 1;
+
+        flip_range(out_buf, pos, flip_block_size);
+
+        if (common_fuzz_stuff(afl, out_buf, len)) return 0;
+
+        flip_range(out_buf, pos, flip_block_size);
+
+        u64 cksum =
+            hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+
+        // printf("Now trying range %d with %d, %s.\n", pos, cur_block_size,
+        //     (cksum == prev_cksum) ? (u8*)"Yes" : (u8*) "Not");
+
+        /* continue until we fail or exceed length */
+        if (cksum == _prev_cksum) {
+
+          cur_block_size *= 2;
+
+          if (cur_block_size >= len - 1 - pos) break;
+
+        } else {
+
+          break;
+
+        }
+
+      }
+
+      if (cur_block_size == MINIMAL_BLOCK_SIZE) {
+
+        /* we failed early on*/
+
+        pos += cur_block_size;
+
+      } else {
+
+        u32 cur_skip_len = (cur_block_size / 2 + pos < len)
+                               ? (cur_block_size / 2)
+                               : (len - pos - 1);
+
+        memset(inf_eff_map + pos, 0, cur_skip_len);
+
+        afl->skipdet_g->inf_prof->inf_skipped_bytes += cur_skip_len;
+
+        pos += cur_skip_len;
+
+      }
+
+    }
+
+    afl->skipdet_g->inf_prof->inf_execs_cost +=
+        (afl->fsrv.total_execs - pre_inf_exec);
+    afl->skipdet_g->inf_prof->inf_time_cost += (get_cur_time() - pre_inf_time);
+    // PFATAL("Done, now have %d bytes skipped, with exec %lld, time %lld.\n",
+    // afl->inf_skipped_bytes, afl->inf_execs_cost, afl->inf_time_cost);
+
+  } else
+
+    memset(inf_eff_map, 1, len);
+
+  new_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  afl->stage_finds[STAGE_INF] += new_hit_cnt - orig_hit_cnt;
+  afl->stage_cycles[STAGE_INF] += afl->stage_cur;
+
+  /****************************
+   * Quick Skip Effective Map *
+   ****************************/
+
+  /* Quick Effective Map Calculation */
+
+  afl->stage_short = "quick";
+  afl->stage_name = "quick eff";
+  afl->stage_cur = 0;
+  afl->stage_max = 32 * 1024;
+
+  orig_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  u32 before_skip_inf = afl->queued_items;
+
+  /* clean all the eff bytes, since previous eff bytes are already fuzzed */
+  u8 *skip_eff_map = afl->queue_cur->skipdet_e->skip_eff_map,
+     *done_inf_map = afl->queue_cur->skipdet_e->done_inf_map;
+
+  if (!skip_eff_map) {
+
+    skip_eff_map = (u8 *)ck_alloc(sizeof(u8) * len);
+    afl->queue_cur->skipdet_e->skip_eff_map = skip_eff_map;
+
+  } else {
+
+    memset(skip_eff_map, 0, sizeof(u8) * len);
+
+  }
+
+  /* restore the starting point */
+  if (!done_inf_map) {
+
+    done_inf_map = (u8 *)ck_alloc(sizeof(u8) * len);
+    afl->queue_cur->skipdet_e->done_inf_map = done_inf_map;
+
+  } else {
+
+    for (afl->stage_cur = 0; afl->stage_cur < len; afl->stage_cur++) {
+
+      if (done_inf_map[afl->stage_cur] == 0) break;
+
+    }
+
+  }
+
+  /* depending on the seed's performance, we could search eff bytes
+     for multiple rounds */
+
+  u8 eff_round_continue = 1, eff_round_done = 0, done_eff = 0, repeat_eff = 0,
+     fuzz_nearby = 0, *non_eff_bytes = 0;
+
+  u64 before_eff_execs = afl->fsrv.total_execs;
+
+  if (getenv("REPEAT_EFF")) repeat_eff = 1;
+  if (getenv("FUZZ_NEARBY")) fuzz_nearby = 1;
+
+  if (fuzz_nearby) {
+
+    non_eff_bytes = (u8 *)ck_alloc(sizeof(u8) * len);
+
+    // clean exec cksum
+    if (common_fuzz_stuff(afl, out_buf, len)) { return 0; }
+    prev_cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+
+  }
+
+  do {
+
+    eff_round_continue = 0;
+    afl->stage_max = 32 * 1024;
+
+    for (; afl->stage_cur < afl->stage_max && afl->stage_cur < len;
+         ++afl->stage_cur) {
+
+      afl->stage_cur_byte = afl->stage_cur;
+
+      if (!inf_eff_map[afl->stage_cur_byte] ||
+          skip_eff_map[afl->stage_cur_byte])
+        continue;
+
+      if (is_det_timeout(before_det_time, 1)) { goto cleanup_skipdet; }
+
+      u8 orig = out_buf[afl->stage_cur_byte], replace = rand_below(afl, 256);
+
+      while (replace == orig) {
+
+        replace = rand_below(afl, 256);
+
+      }
+
+      out_buf[afl->stage_cur_byte] = replace;
+
+      before_skip_inf = afl->queued_items;
+
+      if (common_fuzz_stuff(afl, out_buf, len)) { return 0; }
+
+      out_buf[afl->stage_cur_byte] = orig;
+
+      if (fuzz_nearby) {
+
+        if (prev_cksum ==
+            hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST)) {
+
+          non_eff_bytes[afl->stage_cur_byte] = 1;
+
+        }
+
+      }
+
+      if (afl->queued_items != before_skip_inf) {
+
+        skip_eff_map[afl->stage_cur_byte] = 1;
+        afl->queue_cur->skipdet_e->quick_eff_bytes += 1;
+
+        if (afl->stage_max < MAXIMUM_QUICK_EFF_EXECS) { afl->stage_max *= 2; }
+
+        if (afl->stage_max == MAXIMUM_QUICK_EFF_EXECS && repeat_eff)
+          eff_round_continue = 1;
+
+      }
+
+      done_inf_map[afl->stage_cur_byte] = 1;
+
+    }
+
+    afl->stage_cur = 0;
+    done_eff = 1;
+
+    if (++eff_round_done >= 8) break;
+
+  } while (eff_round_continue);
+
+  new_hit_cnt = afl->queued_items + afl->saved_crashes;
+
+  afl->stage_finds[STAGE_QUICK] += new_hit_cnt - orig_hit_cnt;
+  afl->stage_cycles[STAGE_QUICK] += (afl->fsrv.total_execs - before_eff_execs);
+
+cleanup_skipdet:
+
+  if (fuzz_nearby) {
+
+    u8 *nearby_bytes = (u8 *)ck_alloc(sizeof(u8) * len);
+
+    u32 i = 3;
+    while (i < len) {
+
+      // assume DWORD size, from i - 3 -> i + 3
+      if (skip_eff_map[i]) {
+
+        u32 fill_length = (i + 3 < len) ? 7 : len - i + 2;
+        memset(nearby_bytes + i - 3, 1, fill_length);
+        i += 3;
+
+      } else
+
+        i += 1;
+
+    }
+
+    for (i = 0; i < len; i++) {
+
+      if (nearby_bytes[i] && !non_eff_bytes[i]) skip_eff_map[i] = 1;
+
+    }
+
+    ck_free(nearby_bytes);
+    ck_free(non_eff_bytes);
+
+  }
+
+  if (done_eff) {
+
+    afl->queue_cur->skipdet_e->continue_inf = 0;
+    afl->queue_cur->skipdet_e->done_eff = 1;
+
+  } else {
+
+    afl->queue_cur->skipdet_e->continue_inf = 1;
+
+  }
+
+  return 1;
+
+}
+
diff --git a/src/afl-fuzz-state.c b/src/afl-fuzz-state.c
index 7d6fdfb9..6cf580ce 100644
--- a/src/afl-fuzz-state.c
+++ b/src/afl-fuzz-state.c
@@ -102,7 +102,7 @@ void afl_state_init(afl_state_t *afl, uint32_t map_size) {
   afl->stats_update_freq = 1;
   afl->stats_file_update_freq_msecs = STATS_UPDATE_SEC * 1000;
   afl->stats_avg_exec = 0;
-  afl->skip_deterministic = 1;
+  afl->skip_deterministic = 0;
   afl->sync_time = SYNC_TIME;
   afl->cmplog_lvl = 2;
   afl->min_length = 1;
@@ -140,6 +140,14 @@ void afl_state_init(afl_state_t *afl, uint32_t map_size) {
   afl->fsrv.child_pid = -1;
   afl->fsrv.out_dir_fd = -1;
 
+  /* Init SkipDet */
+  afl->skipdet_g =
+      (struct skipdet_global *)ck_alloc(sizeof(struct skipdet_global));
+  afl->skipdet_g->inf_prof =
+      (struct inf_profile *)ck_alloc(sizeof(struct inf_profile));
+  afl->havoc_prof =
+      (struct havoc_profile *)ck_alloc(sizeof(struct havoc_profile));
+
   init_mopt_globals(afl);
 
   list_append(&afl_states, afl);
diff --git a/src/afl-fuzz-stats.c b/src/afl-fuzz-stats.c
index deb28b7a..4b83ad29 100644
--- a/src/afl-fuzz-stats.c
+++ b/src/afl-fuzz-stats.c
@@ -502,6 +502,44 @@ void maybe_update_plot_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
 
 }
 
+/* Log deterministic stage efficiency */
+
+void plot_profile_data(afl_state_t *afl, struct queue_entry *q) {
+
+  u64 current_ms = get_cur_time() - afl->start_time;
+
+  u32    current_edges = count_non_255_bytes(afl, afl->virgin_bits);
+  double det_finding_rate = (double)afl->havoc_prof->total_det_edge * 100.0 /
+                            (double)current_edges,
+         det_time_rate = (double)afl->havoc_prof->total_det_time * 100.0 /
+                         (double)current_ms;
+
+  u32 ndet_bits = 0;
+  for (u32 i = 0; i < afl->fsrv.map_size; i++) {
+
+    if (afl->skipdet_g->virgin_det_bits[i]) ndet_bits += 1;
+
+  }
+
+  double det_fuzzed_rate = (double)ndet_bits * 100.0 / (double)current_edges;
+
+  fprintf(afl->fsrv.det_plot_file,
+          "[%02lld:%02lld:%02lld] fuzz %d (%d), find %d/%d among %d(%02.2f) "
+          "and spend %lld/%lld(%02.2f), cover %02.2f yet, %d/%d undet bits, "
+          "continue %d.\n",
+          current_ms / 1000 / 3600, (current_ms / 1000 / 60) % 60,
+          (current_ms / 1000) % 60, afl->current_entry, q->fuzz_level,
+          afl->havoc_prof->edge_det_stage, afl->havoc_prof->edge_havoc_stage,
+          current_edges, det_finding_rate,
+          afl->havoc_prof->det_stage_time / 1000,
+          afl->havoc_prof->havoc_stage_time / 1000, det_time_rate,
+          det_fuzzed_rate, q->skipdet_e->undet_bits,
+          afl->skipdet_g->undet_bits_threshold, q->skipdet_e->continue_inf);
+
+  fflush(afl->fsrv.det_plot_file);
+
+}
+
 /* Check terminal dimensions after resize. */
 
 static void check_term_size(afl_state_t *afl) {
diff --git a/src/afl-fuzz.c b/src/afl-fuzz.c
index 8cf6c735..7db1aeb3 100644
--- a/src/afl-fuzz.c
+++ b/src/afl-fuzz.c
@@ -955,14 +955,14 @@ int main(int argc, char **argv_orig, char **envp) {
 
       break;
 
-      case 'D':                                    /* enforce deterministic */
+      case 'D':                                         /* no deterministic */
 
-        afl->skip_deterministic = 0;
+        afl->skip_deterministic = 1;
         break;
 
-      case 'd':                                       /* skip deterministic */
+      case 'd':                                    /* partial deterministic */
 
-        afl->skip_deterministic = 1;
+        afl->skip_deterministic = 0;
         break;
 
       case 'B':                                              /* load bitmap */
@@ -3031,6 +3031,11 @@ stop_fuzzing:
   if (frida_afl_preload) { ck_free(frida_afl_preload); }
 
   fclose(afl->fsrv.plot_file);
+
+  #ifdef INTROSPECTION
+  fclose(afl->fsrv.det_plot_file);
+  #endif
+
   destroy_queue(afl);
   destroy_extras(afl);
   destroy_custom_mutators(afl);