diff --git a/poky/bitbake/lib/bb/utils.py b/poky/bitbake/lib/bb/utils.py
index 73b6cb4..b652a68 100644
--- a/poky/bitbake/lib/bb/utils.py
+++ b/poky/bitbake/lib/bb/utils.py
@@ -27,7 +27,8 @@
 import bb.msg
 import multiprocessing
 import fcntl
-import imp
+import importlib
+from importlib import machinery
 import itertools
 import subprocess
 import glob
@@ -43,7 +44,7 @@
 from ctypes import cdll
 
 logger = logging.getLogger("BitBake.Util")
-python_extensions = [e for e, _, _ in imp.get_suffixes()]
+python_extensions = importlib.machinery.all_suffixes()
 
 
 def clean_context():
@@ -68,8 +69,8 @@
 
 def explode_version(s):
     r = []
-    alpha_regexp = re.compile('^([a-zA-Z]+)(.*)$')
-    numeric_regexp = re.compile('^(\d+)(.*)$')
+    alpha_regexp = re.compile(r'^([a-zA-Z]+)(.*)$')
+    numeric_regexp = re.compile(r'^(\d+)(.*)$')
     while (s != ''):
         if s[0] in string.digits:
             m = numeric_regexp.match(s)
@@ -120,6 +121,10 @@
             return -1
         elif oa > ob:
             return 1
+        elif ca is None:
+            return -1
+        elif cb is None:
+            return 1
         elif ca < cb:
             return -1
         elif ca > cb:
@@ -317,10 +322,13 @@
         error = []
         # split the text into lines again
         body = text.split('\n')
-        error.append("Error in compiling python function in %s, line %s:\n" % (realfile, lineno))
+        error.append("Error in compiling python function in %s, line %s:\n" % (realfile, e.lineno))
         if hasattr(e, "lineno"):
             error.append("The code lines resulting in this error were:")
-            error.extend(_print_trace(body, e.lineno))
+            # e.lineno: line's position in reaflile
+            # lineno: function name's "position -1" in realfile
+            # e.lineno - lineno: line's relative position in function
+            error.extend(_print_trace(body, e.lineno - lineno))
         else:
             error.append("The function causing this error was:")
             for line in body:
@@ -704,15 +712,7 @@
     # CAUTION:  This is dangerous!
     if _check_unsafe_delete_path(topdir):
         raise Exception('bb.utils.prunedir: called with dangerous path "%s", refusing to delete!' % topdir)
-    for root, dirs, files in os.walk(topdir, topdown = False):
-        for name in files:
-            os.remove(os.path.join(root, name))
-        for name in dirs:
-            if os.path.islink(os.path.join(root, name)):
-                os.remove(os.path.join(root, name))
-            else:
-                os.rmdir(os.path.join(root, name))
-    os.rmdir(topdir)
+    remove(topdir, recurse=True)
 
 #
 # Could also use return re.compile("(%s)" % "|".join(map(re.escape, suffixes))).sub(lambda mo: "", var)
@@ -1157,14 +1157,14 @@
 
     var_res = {}
     if match_overrides:
-        override_re = '(_[a-zA-Z0-9-_$(){}]+)?'
+        override_re = r'(_[a-zA-Z0-9-_$(){}]+)?'
     else:
         override_re = ''
     for var in variables:
         if var.endswith('()'):
-            var_res[var] = re.compile('^(%s%s)[ \\t]*\([ \\t]*\)[ \\t]*{' % (var[:-2].rstrip(), override_re))
+            var_res[var] = re.compile(r'^(%s%s)[ \\t]*\([ \\t]*\)[ \\t]*{' % (var[:-2].rstrip(), override_re))
         else:
-            var_res[var] = re.compile('^(%s%s)[ \\t]*[?+:.]*=[+.]*[ \\t]*(["\'])' % (var, override_re))
+            var_res[var] = re.compile(r'^(%s%s)[ \\t]*[?+:.]*=[+.]*[ \\t]*(["\'])' % (var, override_re))
 
     updated = False
     varset_start = ''
@@ -1501,6 +1501,8 @@
       NR_ioprio_set = 251
     elif _unamearch[0] == "i" and _unamearch[2:3] == "86":
       NR_ioprio_set = 289
+    elif _unamearch == "aarch64":
+      NR_ioprio_set = 30
 
     if NR_ioprio_set:
         ioprio = value | (cls << IOPRIO_CLASS_SHIFT)
@@ -1544,12 +1546,9 @@
 def load_plugins(logger, plugins, pluginpath):
     def load_plugin(name):
         logger.debug(1, 'Loading plugin %s' % name)
-        fp, pathname, description = imp.find_module(name, [pluginpath])
-        try:
-            return imp.load_module(name, fp, pathname, description)
-        finally:
-            if fp:
-                fp.close()
+        spec = importlib.machinery.PathFinder.find_spec(name, path=[pluginpath] )
+        if spec:
+            return spec.loader.load_module()
 
     logger.debug(1, 'Loading plugins from %s...' % pluginpath)