RFR: 8032901: WaitForMultipleObjects() return value not handled appropriately

[Aleksej Efimov]

David,

The Windows has a different terminology for mutex objects (much differs 
from the POSIX one). This one link gave me some understanding of it [1].

Here is the MSDN [1] description of what "abandoned mutex" is:
" If a thread terminates without releasing its ownership of a mutex 
object, the mutex object is considered to be abandoned. A waiting thread 
can acquire ownership of an abandoned mutex object, but the wait 
function will return*WAIT_ABANDONED*to indicate that the mutex object is 
abandoned. An abandoned mutex object indicates that an error has 
occurred and that any shared resource being protected by the mutex 
object is in an undefined state. If the thread proceeds as though the 
mutex object had not been abandoned, it is no longer considered 
abandoned after the thread releases its ownership. This restores normal 
behavior if a handle to the mutex object is subsequently specified in a 
wait function."


What does it mean to wait on mutex and ownership of the mutex object:
"Any thread with a handle to a mutex object can use one of thewait 
functions 
<http://msdn.microsoft.com/en-gb/library/windows/desktop/ms687069%28v=vs.85%29.aspx>to 
request ownership of the mutex object. If the mutex object is owned by 
another thread, the wait function blocks the requesting thread until the 
owning thread releases the mutex object using the*ReleaseMutex* 
<http://msdn.microsoft.com/en-gb/library/windows/desktop/ms685066%28v=vs.85%29.aspx>function."

How we can release mutex and wait on already owned mutex:
" After a thread obtains ownership of a mutex, it can specify the same 
mutex in repeated calls to the wait-functions 
<http://msdn.microsoft.com/en-gb/library/windows/desktop/ms687069%28v=vs.85%29.aspx>without 
blocking its execution. This prevents a thread from deadlocking itself 
while waiting for a mutex that it already owns. To release its ownership 
under such circumstances, the thread must call*ReleaseMutex* 
<http://msdn.microsoft.com/en-gb/library/windows/desktop/ms685066%28v=vs.85%29.aspx>once 
for each time that the mutex satisfied the conditions of a wait function."

[1] 
http://msdn.microsoft.com/en-gb/library/windows/desktop/ms684266(v=vs.85).aspx

-Aleksej

On 05/13/2014 04:00 PM, David Holmes wrote:
> I don't understand this one at all. What is an "abandoned mutex"? For 
> that matter why does the code wait on a mutex and an event? Do we 
> already own the mutex? If so what does it mean to wait on it? If not 
> then how can we release it?
>
> ???
>
> Thanks,
> David
>
>
> On 13/05/2014 8:57 PM, Alan Bateman wrote:
>>
>> This is debugger's shared memory transport so cc'ing serviceability-dev
>> as that is there this code is maintained.
>>
>> Is there a test case or any outline of the conditions that cause this? I
>> think that would be useful to understand the issue further.
>>
>> -Alan
>>
>> On 13/05/2014 11:46, Aleksej Efimov wrote:
>>> Hi,
>>>
>>> Can I have a review for 8032901 bug [1] fix [2]. There is a possible
>>> case when 'WaitForMultipleObjects' function can return the
>>> WAIT_ABANDONED_0 [3] error value.
>>> In such case it's better to release the mutex and return error value.
>>> This will prevent other threads to be blocked on abandoned mutex.
>>>
>>> Thank you,
>>> Aleksej
>>>
>>> [1] https://bugs.openjdk.java.net/browse/JDK-8032901
>>> [2] http://cr.openjdk.java.net/~aefimov/8032901/9/webrev.00/
>>> [3]
>>> http://msdn.microsoft.com/en-gb/library/windows/desktop/ms687025(v=vs.85).aspx 
>>>
>>>
>>