On Wed, 4 Jun 2025 13:47:01 GMT, Patricio Chilano Mateo
<pchilanom...@openjdk.org> wrote:
>> Johannes Bechberger has updated the pull request incrementally with one
>> additional commit since the last revision:
>>
>> Fix build
>
> src/hotspot/share/jfr/periodic/sampling/jfrCPUTimeThreadSampler.cpp line 430:
>
>> 428: void JfrCPUTimeThreadSampling::create_sampler(double rate, bool
>> auto_adapt) {
>> 429: assert(_sampler == nullptr, "invariant");
>> 430: _sampler = new JfrCPUSamplerThread(rate, auto_adapt);
>
> If we start a recording on an already running process we have a race here
> where a new thread can create and set its timer before we call init_timers()
> where the signal handler is installed. In that case the program will
> terminate with message “Profiling timer expired" (default action for
> SIGPROF). It can be easily reproduced by adding a delay here and starting a
> recording on a simple test that just creates new threads. We need to add some
> extra check in create_timer_for_thread() or install the signal handler
> earlier.
I created a `has_timer` flag that is checked by `create_timer_for_thread()`
before creating timers and set by `init_timers`. Is this what you envisioned?
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PR Review Comment: https://git.openjdk.org/jdk/pull/25302#discussion_r2126783367
