RFR(XXS): 8234684: JFR crashes when rotating the JFR output during assertion failure

[Mikhailo Seledtsov]

+1

On 11/25/19, 3:21 AM, Erik Gahlin wrote:
> Looks good.
>
> Erik
>
>> On 25 Nov 2019, at 12:11, Markus Gronlund<markus.gronlund at oracle.com>  wrote:
>>
>> Greetings,
>>
>> Please help review the following adjustment:
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8234684
>> Webrev: http://cr.openjdk.java.net/~mgronlun/8234684/webrev/
>> Summary:
>> JFR Event Streaming modified the emergency dump functionality to reuse the newly added flush mechanism in an attempt to avoid having to perform a relatively complex epoch transition during critical shutdown. flush() asserts that the system is not at a safepoint - a valid assumption in the regular case. But because of emergency dump situations, it cannot assert this categorically and needs to be removed.
>>
>> Testing: Manually crashing in a safepoint context
>>
>> Diff:
>> diff -r 6a897a8ef4af -r 5ab7691c56dd src/hotspot/share/jfr/recorder/checkpoint/jfrCheckpointManager.cpp
>> --- a/src/hotspot/share/jfr/recorder/checkpoint/jfrCheckpointManager.cpp        Mon Nov 25 11:08:30 2019 +0100
>> +++ b/src/hotspot/share/jfr/recorder/checkpoint/jfrCheckpointManager.cpp        Mon Nov 25 12:01:41 2019 +0100
>> @@ -461,7 +461,6 @@
>> }
>>
>> size_t JfrCheckpointManager::flush_type_set() {
>> -  assert(!SafepointSynchronize::is_at_safepoint(), "invariant");
>>    size_t elements = 0;
>>    {
>>      JfrCheckpointWriter writer(Thread::current());
>>
>> Thank you
>> Markus