[bitbake-devel] [PATCH] bb.event: fix infinite loop on print_ui_queue

[Aníbal Limón]

On 10/14/2016 03:44 AM, Ed Bartosh wrote:
> On Thu, Oct 13, 2016 at 06:11:34PM -0500, Aníbal Limón wrote:
>> If bitbake ends before _uiready and bb.event.LogHandler was add
>> to the bitbake logger it causes an infinite loop when logging
>> something.
>>
>> The scenario is print_ui_queue is called at exit and executes
>> the log handlers [2] one of them is bb.event.LogHandler this handler
>> appends the same entry to ui_queue causing the inifine loop [3].
>>
>> In order to fix we need to keep track of events already handled to
>> avoid the infinite loop.
>>
>> [YOCTO #10399]
>>
>> [1] https://bugzilla.yoctoproject.org/show_bug.cgi?id=10399#c0
>> [2] http://git.openembedded.org/bitbake/tree/lib/bb/event.py?id=41d9cd41d40b04746c82b4a940dca47df02514fc#n156
>> [3]
>> http://git.openembedded.org/bitbake/tree/lib/bb/event.py?id=41d9cd41d40b04746c82b4a940dca47df02514fc#n164
>>
>> Signed-off-by: Aníbal Limón <anibal.limon at linux.intel.com>
>> ---
>>  lib/bb/event.py | 10 ++++++++++
>>  1 file changed, 10 insertions(+)
>>
>> diff --git a/lib/bb/event.py b/lib/bb/event.py
>> index c5a5f94..8464e06 100644
>> --- a/lib/bb/event.py
>> +++ b/lib/bb/event.py
>> @@ -139,7 +139,11 @@ def print_ui_queue():
>>  
>>          # First check to see if we have any proper messages
>>          msgprint = False
>> +        events_handled = []
>>          for event in ui_queue:
>> +            if event in events_handled:
>> +                continue
>> +
>>              if isinstance(event, logging.LogRecord):
>>                  if event.levelno > logging.DEBUG:
>>                      if event.levelno >= logging.WARNING:
>> @@ -148,14 +152,20 @@ def print_ui_queue():
>>                          logger.addHandler(stdout)
>>                      logger.handle(event)
>>                      msgprint = True
>> +            events_handled.append(event)
>>          if msgprint:
>>              return
>>  
>>          # Nope, so just print all of the messages we have (including debug messages)
>>          logger.addHandler(stdout)
>> +        events_handled = []
>>          for event in ui_queue:
>> +            if event in events_handled:
>> +                continue
>> +
>>              if isinstance(event, logging.LogRecord):
>>                  logger.handle(event)
>> +            events_handled.append(event)
>>  
>>  def fire_ui_handlers(event, d):
>>      global _thread_lock
> 
> Would using full slice of ui_queue work the same way?

Yes it will work and is more simple, i'll send v2.

	alimon

> 
> @@ -139,7 +139,7 @@ def print_ui_queue():
> 
>          # First check to see if we have any proper messages
>          msgprint = False
> -        for event in ui_queue:
> +        for event in ui_queue[:]:
>              if isinstance(event, logging.LogRecord):
>                  if event.levelno > logging.DEBUG:
>                      if event.levelno >= logging.WARNING:
> 
> 
> --
> Regards,
> Ed
> 

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