Re: [Qemu-devel] Aborts in iotest 169

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

24.01.2019 12:29, Vladimir Sementsov-Ogievskiy wrote:
> 23.01.2019 18:48, Max Reitz wrote:
>> Hi,
>>
>> When running 169 in parallel (e.g. like so:
>>
>> $ while TEST_DIR=/tmp/t0 ./check -T -qcow2 169; do; done
>> $ while TEST_DIR=/tmp/t1 ./check -T -qcow2 169; do; done
>> $ while TEST_DIR=/tmp/t2 ./check -T -qcow2 169; do; done
>> $ while TEST_DIR=/tmp/t3 ./check -T -qcow2 169; do; done
>>
>> in four different shells), I get aborts:
>>
>> (Often I get segfaults, but that's because of
>> http://lists.nongnu.org/archive/html/qemu-devel/2018-12/msg05579.html --
>> feel free to apply the attached patch to make them go away)
>>
>>
>> WARNING:qemu:qemu received signal 6:
>> build/tests/qemu-iotests/../../x86_64-softmmu/qemu-system-x86_64
>> -chardev socket,id=mon,path=/tmp/t0/tmpbX30XU/qemua-25745-monitor.sock
>> -mon chardev=mon,mode=control -display none -vga none -qtest
>> unix:path=/tmp/t0/qemua-25745-qtest.sock -machine accel=qtest
>> -nodefaults -machine accel=qtest -drive
>> if=virtio,id=drive0,file=/tmp/t0/disk_a,format=qcow2,cache=writeback
>> .................E..
>> ======================================================================
>> ERROR:
>> test_do_test_migration_resume_source_not_persistent__not_migbitmap
>> (__main__.TestDirtyBitmapMigration)
>> ----------------------------------------------------------------------
>> Traceback (most recent call last):
>>    File "169", line 206, in <lambda>
>>      setattr(klass, 'test_' + method + name, lambda self: mc(self))
>>    File "169", line 113, in do_test_migration_resume_source
>>      self.check_bitmap(self.vm_a, sha256)
>>    File "169", line 72, in check_bitmap
>>      node='drive0', name='bitmap0')
>>    File "tests/qemu-iotests/../../scripts/qemu.py", line 369, in qmp
>>      return self._qmp.cmd(cmd, args=qmp_args)
>>    File "tests/qemu-iotests/../../scripts/qmp/qmp.py", line 191, in cmd
>>      return self.cmd_obj(qmp_cmd)
>>    File "tests/qemu-iotests/../../scripts/qmp/qmp.py", line 174, in cmd_obj
>>      resp = self.__json_read()
>>    File "tests/qemu-iotests/../../scripts/qmp/qmp.py", line 82, in
>> __json_read
>>      data = self.__sockfile.readline()
>>    File "/usr/lib64/python2.7/socket.py", line 451, in readline
>>      data = self._sock.recv(self._rbufsize)
>> error: [Errno 104] Connection reset by peer
>>
>> ----------------------------------------------------------------------
>> Ran 20 tests
>>
>> FAILED (errors=1)
>>
>>
>> Or:
>>
>> WARNING:qemu:qemu received signal 6:
>> build/tests/qemu-iotests/../../x86_64-softmmu/qemu-system-x86_64
>> -chardev socket,id=mon,path=/tmp/t3/tmp0pllWD/qemua-3445-monitor.sock
>> -mon chardev=mon,mode=control -display none -vga none -qtest
>> unix:path=/tmp/t3/qemua-3445-qtest.sock -machine accel=qtest -nodefaults
>> -machine accel=qtest -drive
>> if=virtio,id=drive0,file=/tmp/t3/disk_a,format=qcow2,cache=writeback
>> WARNING:qemu:qemu received signal 6:
>> build/tests/qemu-iotests/../../x86_64-softmmu/qemu-system-x86_64
>> -chardev socket,id=mon,path=/tmp/t3/tmp0pllWD/qemua-3445-monitor.sock
>> -mon chardev=mon,mode=control -display none -vga none -qtest
>> unix:path=/tmp/t3/qemua-3445-qtest.sock -machine accel=qtest -nodefaults
>> -machine accel=qtest -drive
>> if=virtio,id=drive0,file=/tmp/t3/disk_a,format=qcow2,cache=writeback
>>
>> ...................F
>> ======================================================================
>> FAIL: test_do_test_migration_resume_source_persistent__not_migbitmap
>> (__main__.TestDirtyBitmapMigration)
>> ----------------------------------------------------------------------
>> Traceback (most recent call last):
>>    File "169", line 206, in <lambda>
>>      setattr(klass, 'test_' + method + name, lambda self: mc(self))
>>    File "169", line 125, in do_test_migration_resume_source
>>      self.assertEqual(log, '')
>> AssertionError: "qemu-system-x86_64: invalid runstate transition:
>> 'running' -> 'postmigrate'\n" != ''
>>
>> ----------------------------------------------------------------------
>> Ran 20 tests
>>
>> FAILED (failures=1)
>>
>>
>> The backtrace always goes like this:
>>
>> (gdb) bt
>> #0  0x00007f0acf5cc53f in raise () at /lib64/libc.so.6
>> #1  0x00007f0acf5b6895 in abort () at /lib64/libc.so.6
>> #2  0x000055a46ebbb1a6 in runstate_set (new_state=RUN_STATE_POSTMIGRATE)
>> at vl.c:742
>> #3  0x000055a46ebbb1a6 in runstate_set
>> (new_state=new_state@entry=RUN_STATE_POSTMIGRATE) at vl.c:730
>> #4  0x000055a46ed39129 in migration_iteration_finish (s=0x55a4708be000)
>> at migration/migration.c:2972
>> #5  0x000055a46ed39129 in migration_thread
>> (opaque=opaque@entry=0x55a4708be000) at migration/migration.c:3130
>> #6  0x000055a46eea665a in qemu_thread_start (args=<optimized out>) at
>> util/qemu-thread-posix.c:502
>>
>>
>> #7  0x00007f0acf76258e in start_thread () at /lib64/libpthread.so.0
>> #8  0x00007f0acf6916a3 in clone () at /lib64/libc.so.6
>> (gdb) frame 2
>> #2  0x000055a46ebbb1a6 in runstate_set (new_state=RUN_STATE_POSTMIGRATE)
>> at vl.c:742
>> 742             abort();
>> (gdb) print current_run_state
>> $1 = RUN_STATE_RUNNING
>>
>>
>> Neither of migration or runstates are my strong suite, so I thought I'd
>> report it before diving into it.
>>
>> Max
>>
> 
> [...]
> 450556@1548321072.888979:migrate_set_state new state active
> 450556@1548321072.889022:migration_thread_setup_complete
> 450556@1548321072.988275:migrate_transferred transferred 985298 time_spent 100 bandwidth 9852 max_size 2955894
> 450556@1548321072.988283:migration_bitmap_sync_start
> 450556@1548321072.988293:migration_bitmap_sync_end dirty_pages 32898
> 450556@1548321072.988495:migration_thread_low_pending 2048
> migration_completion
> 450556@1548321072.988541:runstate_set current_state 9 new_state 7
> 450556@1548321072.988780:migration_bitmap_sync_start
> 450556@1548321072.988790:migration_bitmap_sync_end dirty_pages 32898
> 450556@1548321072.993112:migrate_global_state_pre_save saved state: running
> [1] 450556@1548321072.993237:migrate_set_state new state completed
> 450549@1548321072.993668:handle_qmp_command mon 0x55aebef99830 req: {"execute": "x-debug-block-dirty-bitmap-sha256", "arguments": {"name": "bitmap0", "node": "drive0"}}
> 450556@1548321072.993697:migration_thread_after_loop
> [2] 450549@1548321072.993917:handle_qmp_command mon 0x55aebef99830 req: {"execute": "cont"}
> 450476@1548321072.994461:runstate_set current_state 7 new_state 9
> qemu-system-x86_64: invalid runstate transition: 'running' -> 'postmigrate'
> 
> 
> Aha, so, in test we wait for MIGRATION COMPLETED [1] and run qmp_cont [2] and go to RUNNING.
> then in migration thread we go to migration_iteration_finish() and fail to go to POSTMIGRATE.
> (note, that this testcase is about resuming source after migration)
> 
> So, fix for test may be additionally wait for POSTMIGRATE, not only for MIGRATION COMPLETION.
> 
> But how to fix Qemu not to crash? May be, forbid some transitions (FINISH_MIGRATE -> RUNNING),
>   or at least error-out qmp_cont if runstate is  FINISH_MIGRATE?
> 
> 
> 


Ok, this seems to fix test for me:

diff --git a/tests/qemu-iotests/169 b/tests/qemu-iotests/169
index 527aebd0cb..dd98168c8d 100755
--- a/tests/qemu-iotests/169
+++ b/tests/qemu-iotests/169
@@ -102,6 +102,10 @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):
              event = self.vm_a.event_wait('MIGRATION')
              if event['data']['status'] == 'completed':
                  break
+        while True:
+            result = self.vm_a.qmp('query-status')
+            if (result['return']['status'] == 'postmigrate'):
+                break

          # test that bitmap is still here
          removed = (not migrate_bitmaps) and persistent

-


And this is the full diff of the test I used, to skip checking log (as I enabled traces) and to skip all other test-cases:

(hmm, we definitely need simple way to run one test case from test, without editing it)

diff --git a/tests/qemu-iotests/169 b/tests/qemu-iotests/169
index 527aebd0cb..dd98168c8d 100755
--- a/tests/qemu-iotests/169
+++ b/tests/qemu-iotests/169
@@ -102,6 +102,10 @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):
              event = self.vm_a.event_wait('MIGRATION')
              if event['data']['status'] == 'completed':
                  break
+        while True:
+            result = self.vm_a.qmp('query-status')
+            if (result['return']['status'] == 'postmigrate'):
+                break

          # test that bitmap is still here
          removed = (not migrate_bitmaps) and persistent
@@ -117,12 +121,12 @@ class TestDirtyBitmapMigration(iotests.QMPTestCase):

          # catch 'Could not reopen qcow2 layer: Bitmap already exists'
          # possible error
-        log = self.vm_a.get_log()
-        log = re.sub(r'^\[I \d+\.\d+\] OPENED\n', '', log)
-        log = re.sub(r'^(wrote .* bytes at offset .*\n.*KiB.*ops.*sec.*\n){3}',
-                     '', log)
-        log = re.sub(r'\[I \+\d+\.\d+\] CLOSED\n?$', '', log)
-        self.assertEqual(log, '')
+        #log = self.vm_a.get_log()
+        #log = re.sub(r'^\[I \d+\.\d+\] OPENED\n', '', log)
+        #log = re.sub(r'^(wrote .* bytes at offset .*\n.*KiB.*ops.*sec.*\n){3}',
+                     #'', log)
+        #log = re.sub(r'\[I \+\d+\.\d+\] CLOSED\n?$', '', log)
+        #self.assertEqual(log, '')

          # test that bitmap is still persistent
          self.vm_a.launch()
@@ -211,14 +215,16 @@ for cmb in list(itertools.product((True, False), repeat=4)):
      name += '_online' if cmb[2] else '_offline'
      name += '_shared' if cmb[3] else '_nonshared'

-    inject_test_case(TestDirtyBitmapMigration, name, 'do_test_migration',
+    if False:
+        inject_test_case(TestDirtyBitmapMigration, name, 'do_test_migration',
                       *list(cmb))

  for cmb in list(itertools.product((True, False), repeat=2)):
      name = ('_' if cmb[0] else '_not_') + 'persistent_'
      name += ('_' if cmb[1] else '_not_') + 'migbitmap'

-    inject_test_case(TestDirtyBitmapMigration, name,
+    if name == '_persistent__migbitmap':
+        inject_test_case(TestDirtyBitmapMigration, name,
                       'do_test_migration_resume_source', *list(cmb))

  if __name__ == '__main__':
diff --git a/tests/qemu-iotests/169.out b/tests/qemu-iotests/169.out
index 3a89159833..ae1213e6f8 100644
--- a/tests/qemu-iotests/169.out
+++ b/tests/qemu-iotests/169.out
@@ -1,5 +1,5 @@
-....................
+.
  ----------------------------------------------------------------------
-Ran 20 tests
+Ran 1 tests

  OK



-- 
Best regards,
Vladimir