1 files changed, 16 insertions, 5 deletions

diff --git a/frida_mode/src/instrument/instrument.c b/frida_mode/src/instrument/instrument.c
index bf102a82..46ed1a34 100644
--- a/frida_mode/src/instrument/instrument.c
+++ b/frida_mode/src/instrument/instrument.c
@@ -32,12 +32,13 @@ char *   instrument_coverage_unstable_filename = NULL;
 
 static GumStalkerTransformer *transformer = NULL;
 
-__attribute__((aligned(0x1000))) __thread guint64 instrument_previous_pc = 0;
-
 static GumAddress previous_rip = 0;
 static GumAddress previous_end = 0;
 static u8 *       edges_notified = NULL;
 
+__thread guint64  instrument_previous_pc;
+__thread guint64 *instrument_previous_pc_addr = NULL;
+
 typedef struct {
 
   GumAddress address;
@@ -105,8 +106,14 @@ __attribute__((hot)) static void on_basic_block(GumCpuContext *context,
   guint16      current_end = ctx->end;
   guint64      current_pc = instrument_get_offset_hash(current_rip);
   guint64      edge;
+  if (instrument_previous_pc_addr == NULL) {
+
+    instrument_previous_pc_addr = &instrument_previous_pc;
+    *instrument_previous_pc_addr = instrument_hash_zero;
+
+  }
 
-  edge = current_pc ^ instrument_previous_pc;
+  edge = current_pc ^ *instrument_previous_pc_addr;
 
   instrument_increment_map(edge);
 
@@ -136,7 +143,7 @@ __attribute__((hot)) static void on_basic_block(GumCpuContext *context,
   previous_end = current_end;
 
   gsize map_size_pow2 = util_log2(__afl_map_size);
-  instrument_previous_pc = util_rotate(current_pc, 1, map_size_pow2);
+  *instrument_previous_pc_addr = util_rotate(current_pc, 1, map_size_pow2);
 
 }
 
@@ -393,7 +400,11 @@ GumStalkerTransformer *instrument_get_transformer(void) {
 
 void instrument_on_fork() {
 
-  instrument_previous_pc = instrument_hash_zero;
+  if (instrument_previous_pc_addr != NULL) {
+
+    *instrument_previous_pc_addr = instrument_hash_zero;
+
+  }
 
 }