On 5/07/2018 7:58 PM, David Holmes wrote:
<sigh> Solaris compiler complains about doing a return from inside a
do-while loop. I'll have to rework part of the fix tomorrow.
Webrev updated in-place. The only change is to the makefile to disable a
warning:
+ ifeq ($(TOOLCHAIN_TYPE), solstudio)
+ BUILD_HOTSPOT_JTREG_LIBRARIES_CFLAGS_libji06t001 +=
-erroff=E_END_OF_LOOP_CODE_NOT_REACHED
+ endif
+
David
-----
David
On 5/07/2018 6:19 PM, David Holmes wrote:
Bug: https://bugs.openjdk.java.net/browse/JDK-8205878
Webrev: http://cr.openjdk.java.net/~dholmes/8205878/webrev/
Problem:
The tests create native threads that attach to the VM through
JNI_AttachCurrentThread but which then terminate without detaching
themselves. When the VM exits and we're using Flight Recorder
"dumponexit" this leads to a call to VM_PrintThreads that in part
wants to print the per-thread CPU usage. When we encounter the threads
that have terminated already the low level pthread_getcpuclockid calls
returns ESRCH but the code doesn't expect that and so fails an assert
in debug mode and can SEGV in product mode.
Solution:
Serviceability-side: fix the tests
Change the tests so that the threads detach before terminating. The
two tests are (surprisingly) written in completely different styles,
so the solution also takes on two different styles.
Runtime-side: make the VM more robust in the fact of JNI attached
threads that terminate before detaching, and add a regression test
I took a good look at the low-level code for interacting with
arbitrary threads and as far as I can see the problem only exists for
this one case of pthread_getcpuclockid on Linux. Elsewhere the
potential for a library call failure just reports an error value (such
as -1 for the cpu time used).
So the fix is simply to allow for ESRCH when calling
pthread_getcpuclockid and return -1 for the cpu usage in that case.
I created a new regression test to create a new native thread, attach
it and then let it terminate while still attached. The java code then
calls various Thread and ThreadMXBean functions on it to ensure there
are no crashes or unexpected exceptions.
Testing:
- old tests with fixed run-time
- old run-time with fixed tests
- mach tier4 (which exposed the problem - that's where we enable
Flight recorder for the tests) [in progress]
- mach5 tier 1-3 for good measure [in progress]
- new regression test
Thanks,
David
