@@ -33,6 +33,7 @@ static PyObject* cpyprof_PyEval_EvalFrameEx(PyFrameObject *, int);
 */
 #define CODE_ADDR_TO_UID(co)  (((unsigned long)(co)))
 
+static volatile int is_enabled = 0;
 
 #define SINGLE_BUF_SIZE (8192 - 2 * sizeof(unsigned int))
 #if defined(__unix__) || defined(__APPLE__)
@@ -43,7 +44,6 @@ static PyObject* cpyprof_PyEval_EvalFrameEx(PyFrameObject *, int);
 
 static destructor Original_code_dealloc = 0;
 static ptrdiff_t mainloop_sp_offset;
-static int is_enabled = 0;
 
 static void* get_virtual_ip(char* sp)
 {
 
@@ -260,12 +260,14 @@ static int remove_sigprof_timer(void) {
 static void atfork_disable_timer(void) {
     if (profile_interval_usec > 0) {
         remove_sigprof_timer();
+        is_enabled = 0;
     }
 }
 
 static void atfork_enable_timer(void) {
     if (profile_interval_usec > 0) {
         install_sigprof_timer();
+        is_enabled = 1;
     }
 }
 
 
@@ -61,9 +61,15 @@ def read_prof(fileobj, virtual_ips_only=False): #
     all = 0
     interp_name = None
     version = 0
+    c = False
 
     while True:
         marker = fileobj.read(1)
+        #print (fileobj.tell(), marker)
+        if fileobj.tell() > 226264155 - 100:
+            c = True
+            #import pdb
+            #pdb.set_trace()
         if marker == MARKER_HEADER:
             assert not version, "multiple headers"
             version, = struct.unpack("!h", fileobj.read(2))
@@ -106,6 +112,8 @@ def read_prof(fileobj, virtual_ips_only=False): #
         elif marker == MARKER_VIRTUAL_IP:
             unique_id = read_word(fileobj)
             name = read_string(fileobj)
+            if c:
+                print (unique_id, name, len(name), fileobj.tell())
             all += len(name)
             if PY3:
                 name = name.decode()
@@ -115,7 +123,7 @@ def read_prof(fileobj, virtual_ips_only=False): #
             #    symmap = read_ranges(fileobj.read())
             break
         else:
-            assert not marker
+            assert not marker, (fileobj.tell(), repr(marker))
             break
     virtual_ips.sort() # I think it's sorted, but who knows
     if virtual_ips_only:
Original file line number	Diff line number	Diff line change
`@@ -260,12 +260,14 @@ static int remove_sigprof_timer(void) {`
`260`	`260`	`static void atfork_disable_timer(void) {`
`261`	`261`	`if (profile_interval_usec > 0) {`
`262`	`262`	`remove_sigprof_timer();`
	`263`	`+ is_enabled = 0;`
`263`	`264`	`}`
`264`	`265`	`}`
`265`	`266`
`266`	`267`	`static void atfork_enable_timer(void) {`
`267`	`268`	`if (profile_interval_usec > 0) {`
`268`	`269`	`install_sigprof_timer();`
	`270`	`+ is_enabled = 1;`
`269`	`271`	`}`
`270`	`272`	`}`
`271`	`273`