Bug#929728: systemd autopkgtest 'storage' fails adding/rmmoding scsi_debug

[Dan Streetman]

Package: systemd
Version: 241-5
Severity: normal
Tags: patch
User: ubuntu-devel at lists.ubuntu.com
Usertags: origin-ubuntu eoan ubuntu-patch

Dear Maintainer,

'storage' test fails on some archs/releases trying to modprobe and/or rmmod scsi_debug.

-- Package-specific info:


  * d/t/storage:
    - fix handling of scsi_debug module, test drives (LP: #1829347)


Thanks for considering the patch.


-- System Information:
Debian Release: buster/sid
  APT prefers disco-updates
  APT policy: (500, 'disco-updates'), (500, 'disco-security'), (500, 'disco'), (100, 'disco-backports')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.0.0-13-generic (SMP w/24 CPU cores)
Kernel taint flags: TAINT_WARN
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages systemd is related to:
pn  dracut           <none>
ii  initramfs-tools  0.131ubuntu19
ii  udev             240-6ubuntu5
-------------- next part --------------
diff -Nru systemd-241/debian/tests/storage systemd-241/debian/tests/storage
--- systemd-241/debian/tests/storage	2019-05-24 16:58:59.000000000 -0400
+++ systemd-241/debian/tests/storage	2019-05-29 11:52:19.000000000 -0400
@@ -12,40 +12,69 @@
 from glob import glob
 
 
- at unittest.skipIf(os.path.isdir('/sys/module/scsi_debug'),
-                 'The scsi_debug module is already loaded')
+SCSI_DEBUG_DIR='/sys/bus/pseudo/drivers/scsi_debug'
+
 class FakeDriveTestBase(unittest.TestCase):
     @classmethod
     def setUpClass(klass):
-        # create a fake SCSI hard drive
-        subprocess.check_call(['modprobe', 'scsi_debug', 'dev_size_mb=32'])
+        if not os.path.isdir(SCSI_DEBUG_DIR):
+            subprocess.call(['modprobe', 'scsi_debug', 'dev_size_mb=32'],
+                            stderr=subprocess.DEVNULL)
+            # if still not available, we can't run any of our tests
+            if not os.path.isdir(SCSI_DEBUG_DIR):
+                klass.skipTest('scsi_debug module not loaded')
+
+    def setUp(self):
+        # remove any existing drives, then add back one for us to use
+        self.remove_scsi_debug_drives()
+        with open(os.path.join(SCSI_DEBUG_DIR, 'add_host'), 'r+') as f:
+            print('Adding scsi_debug drive')
+            f.write('1')
+            for wait in range(10):
+                f.seek(0)
+                if f.read().strip() == '1':
+                    break
+                time.sleep(0.1)
+            else:
+                self.skipTest('Could not add scsi_debug drive to test')
         # wait until drive got created
         sys_dirs = []
-        while not sys_dirs:
-            sys_dirs = glob('/sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*:*/block')
+        for tries in range(100):
+            sys_dirs = glob(os.path.join(SCSI_DEBUG_DIR,
+                                         'adapter*/host*/target*/*:*/block'))
+            if sys_dirs:
+                break
             time.sleep(0.1)
-        assert len(sys_dirs) == 1
+        if len(sys_dirs) < 1:
+            self.skipTest('could not find scsi_debug block device')
+        elif len(sys_dirs) > 1:
+            self.skipTest('too many scsi_debug block devices (%s)' % len(sys_dirs))
         devs = os.listdir(sys_dirs[0])
         assert len(devs) == 1
-        klass.device = '/dev/' + devs[0]
-
-    @classmethod
-    def tearDownClass(klass):
-        # create a fake SCSI hard drive
-        subprocess.check_call(['rmmod', 'scsi_debug'])
+        self.device = '/dev/' + devs[0]
 
     def tearDown(self):
-        # clear drive
-        with open(self.device, 'wb') as f:
-            block = b'0' * 1048576
-            try:
-                while True:
-                    f.write(block)
-            except OSError:
-                pass
+        self.remove_scsi_debug_drives()
         subprocess.check_call(['udevadm', 'settle'])
         subprocess.check_call(['systemctl', 'daemon-reload'])
 
+    def remove_scsi_debug_drives(self):
+        with open(os.path.join(SCSI_DEBUG_DIR, 'add_host'), 'r+') as f:
+            n = f.read().strip()
+            f.seek(0)
+            if n == '0':
+                return
+            print('Removing %s scsi_debug test drive(s)' % n)
+            f.write('-%s' % n)
+            for wait in range(50):
+                f.seek(0)
+                n = f.read().strip()
+                if n == '0':
+                    break
+                time.sleep(0.1)
+            else:
+                self.skipTest('Could not remove %s scsi_debug drives' % n)
+
 
 class CryptsetupTest(FakeDriveTestBase):
     def setUp(self):
@@ -215,6 +244,7 @@
         self.format_luks()
         with open('/etc/crypttab', 'w') as f:
             f.write('%s %s none luks,tmp\n' % (self.plaintext_name, self.device))
+        self.apply('cryptsetup.target')
 
         mountpoint = '/run/crypt1.systemdtest'
         os.mkdir(mountpoint)
@@ -230,17 +260,15 @@
         self.apply('local-fs.target')
 
         # should be mounted
-        found = False
         with open('/proc/mounts') as f:
             for line in f:
                 fields = line.split()
                 if fields[0] == self.plaintext_dev:
                     self.assertEqual(fields[1], mountpoint)
                     self.assertEqual(fields[2], 'ext2')
-                    found = True
                     break
-        if not found:
-            self.fail('%s is not mounted' % self.plaintext_dev)
+            else:
+                self.fail('%s is not mounted' % self.plaintext_dev)
 
 
 if __name__ == '__main__':