poky/bitbake/lib
Richard Purdie 83fda1bb2e bitbake: event/utils: Avoid deadlock from lock_timeout() and recursive events
We've been seeing intermittent failures on Ubuntu 22.04 in oe-selftest which
were problematic to debug. The failure was inside lock_timeout and once that was
identified and the backtrace obtained, the problem becomes clearer:

  File "X/bitbake/lib/bb/server/process.py", line 466, in idle_thread_internal
    retval = function(self, data, False)
  File "X/bitbake/lib/bb/command.py", line 123, in runAsyncCommand
    self.cooker.updateCache()
  File "X/bitbake/lib/bb/cooker.py", line 1629, in updateCache
    self.parser = CookerParser(self, mcfilelist, total_masked)
  File "X/bitbake/lib/bb/cooker.py", line 2141, in __init__
    self.bb_caches = bb.cache.MulticonfigCache(self.cfgbuilder, self.cfghash, cooker.caches_array)
  File "X/bitbake/lib/bb/cache.py", line 772, in __init__
    loaded += c.prepare_cache(progress)
  File "X/bitbake/lib/bb/cache.py", line 435, in prepare_cache
    loaded = self.load_cachefile(progress)
  File "X/bitbake/lib/bb/cache.py", line 516, in load_cachefile
    progress(cachefile.tell() + previous_progress)
  File "X/bitbake/lib/bb/cache.py", line 751, in progress
    bb.event.fire(bb.event.CacheLoadProgress(current_progress, cachesize),
  File "X/bitbake/lib/bb/event.py", line 234, in fire
    fire_ui_handlers(event, d)
  File "X/bitbake/lib/bb/event.py", line 210, in fire_ui_handlers
    _ui_handlers[h].event.send(event)
  File "X/bitbake/lib/bb/cooker.py", line 117, in send
    str_event = codecs.encode(pickle.dumps(event), \'base64\').decode(\'utf-8\')
  File "/usr/lib/python3.10/asyncio/sslproto.py", line 320, in __del__
    _warn(f"unclosed transport {self!r}", ResourceWarning, source=self)
  File "/usr/lib/python3.10/warnings.py", line 109, in _showwarnmsg
    sw(msg.message, msg.category, msg.filename, msg.lineno,
  File "X/bitbake/lib/bb/main.py", line 113, in _showwarning
    warnlog.warning(s)
  File "/usr/lib/python3.10/logging/__init__.py", line 1489, in warning
    self._log(WARNING, msg, args, **kwargs)
  File "/usr/lib/python3.10/logging/__init__.py", line 1624, in _log
    self.handle(record)
  File "/usr/lib/python3.10/logging/__init__.py", line 1634, in handle
    self.callHandlers(record)
  File "/usr/lib/python3.10/logging/__init__.py", line 1696, in callHandlers
    hdlr.handle(record)
  File "/usr/lib/python3.10/logging/__init__.py", line 968, in handle
    self.emit(record)
  File "X/bitbake/lib/bb/event.py", line 778, in emit
    fire(record, None)
  File "X/bitbake/lib/bb/event.py", line 234, in fire
    fire_ui_handlers(event, d)
  File "X/bitbake/lib/bb/event.py", line 197, in fire_ui_handlers
    with bb.utils.lock_timeout(_thread_lock):
  File "/usr/lib/python3.10/contextlib.py", line 135, in __enter__
    return next(self.gen)
  File "X/bitbake/lib/bb/utils.py", line 1888, in lock_timeout
    bb.server.process.serverlog("Couldn\'t get the lock for 5 mins, timed out, exiting. %s" % traceback.format_stack())

or put in simpler terms, whilst sending an event(), an unrelated warning
message happens to be triggered from asyncio:

/usr/lib/python3.10/asyncio/sslproto.py:320: ResourceWarning: unclosed transport <asyncio.sslproto._SSLProtocolTransport object at 0x7f0e797d3100>

which triggers a second event() which can't be sent as we're already
in the critcal section and already hold the lock.

That warning is due to the version of asyncio used on Ubuntu 22.04 with
python 3.10 and that comined with timing issues explains why we don't
see it on other python versions or distros.

We can't handle the second event as the lock is there to serialise the
events. Instead, we queue the event and then process the queue later.

Add a new version of lock_timeout which allows us to handle the situation
more gracefully.

(Bitbake rev: 696c2c1ef095f8b11c7d2eff36fae50f58c62e5e)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 2c590ff1aff89d23b25ce808650f200013a1e6af)
Signed-off-by: Steve Sakoman <steve@sakoman.com>
2025-03-15 06:40:07 -07:00
..
bb bitbake: event/utils: Avoid deadlock from lock_timeout() and recursive events 2025-03-15 06:40:07 -07:00
bblayers bitbake: bblayers/query: Fix using "removeprefix" string method 2025-02-21 06:25:05 -08:00
bs4 bitbake: bitbake/lib/bs4/tests/test_tree.py: python 3.12 regex 2024-02-13 13:52:10 +00:00
hashserv bitbake: hashserv: client: Add batch stream API 2024-06-06 06:53:49 -07:00
layerindexlib bitbake: layerindexlib: fix missing layer branch backtrace 2024-02-27 11:36:38 +00:00
ply bitbake: utils/ply: Update md5 to better report errors with hashlib 2022-10-26 12:32:08 +01:00
progressbar bitbake: bitbake: progressbar: accept value over initial maxval 2024-02-23 14:34:05 +00:00
prserv bitbake: prserv: remove unnecessary code 2024-04-14 06:31:45 +01:00
simplediff bitbake: lib/bb/siggen: show word-diff for single-line values containing spaces 2017-04-10 23:00:32 +01:00
toaster bitbake: toaster/tests: Bug-fix ToasterTable show_rows testcases 2024-01-10 13:55:33 +00:00
codegen.py bitbake: codegen: cleanup deprecated AST usages 2023-11-14 23:39:53 +00:00
pyinotify.py bitbake: pyinotify.py: Simplify identification of which event has occurred 2022-04-14 09:48:33 +01:00