[PATCH] kunit: Fix kunit.py run --build_dir='<foo>' fails on "unclean" trees

[Vitor Massaru Iha <vitor@massaru.org>]

Fix this bug: https://bugzilla.kernel.org/show_bug.cgi?id=205219

For some reason, the environment variable ARCH is used instead of ARCH
passed as an argument, this patch uses a copy of the env, but using
ARCH=um and CROSS_COMPILER='' to avoid this problem.

This patch doesn't change the user's environment variables, avoiding
side effects.

Signed-off-by: Vitor Massaru Iha <vitor@massaru.org>
---
 tools/testing/kunit/kunit_kernel.py | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index d99ae75ef72f..0cb1f81ac8f2 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -15,6 +15,7 @@ import kunit_config
 
 KCONFIG_PATH = '.config'
 kunitconfig_path = '.kunitconfig'
+env = dict(os.environ.copy(), ARCH='um', CROSS_COMPILE='')
 
 class ConfigError(Exception):
 	"""Represents an error trying to configure the Linux kernel."""
@@ -36,22 +37,22 @@ class LinuxSourceTreeOperations(object):
 			raise ConfigError(e.output)
 
 	def make_olddefconfig(self, build_dir):
-		command = ['make', 'ARCH=um', 'olddefconfig']
+		command = ['make', 'olddefconfig']
 		if build_dir:
 			command += ['O=' + build_dir]
 		try:
-			subprocess.check_output(command)
+			subprocess.check_output(command, env=env)
 		except OSError as e:
 			raise ConfigError('Could not call make command: ' + e)
 		except subprocess.CalledProcessError as e:
 			raise ConfigError(e.output)
 
 	def make(self, jobs, build_dir):
-		command = ['make', 'ARCH=um', '--jobs=' + str(jobs)]
+		command = ['make', '--jobs=' + str(jobs)]
 		if build_dir:
 			command += ['O=' + build_dir]
 		try:
-			subprocess.check_output(command)
+			subprocess.check_output(command, env=env)
 		except OSError as e:
 			raise BuildError('Could not call execute make: ' + e)
 		except subprocess.CalledProcessError as e:
@@ -66,7 +67,8 @@ class LinuxSourceTreeOperations(object):
 			[linux_bin] + params,
 			stdin=subprocess.PIPE,
 			stdout=subprocess.PIPE,
-			stderr=subprocess.PIPE)
+			stderr=subprocess.PIPE,
+			env=env)
 		process.wait(timeout=timeout)
 		return process
 
-- 
2.21.1