The following test failed in the JDK15 CI:

gc/z/TestSmallHeap.java

Here's a snippet from the log file:

#section:main
----------messages:(4/320)----------
command: main -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx8M gc.z.TestSmallHeap
reason: User specified action: run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+UseZGC -Xlog:gc,gc+init,gc+heap -Xmx8M gc.z.TestSmallHeap
Mode: othervm [/othervm specified]
elapsed time (seconds): 0.967
----------configuration:(0/0)----------
----------System.out:(334/39140)----------
[0.007s][info][gc,init] Initializing The Z Garbage Collector
[0.007s][info][gc,init] Version: 15-ea+14-522 (release)
[0.007s][info][gc,init] NUMA Support: Disabled
[0.007s][info][gc,init] CPUs: 8 total, 8 available
[0.007s][info][gc,init] Memory: 60117M
[0.007s][info][gc,init] Large Page Support: Disabled
[0.007s][info][gc,init] Medium Page Size: N/A
[0.007s][info][gc,init] Workers: 1 parallel, 1 concurrent
[0.011s][info][gc,init] Address Space Type: Contiguous/Unrestricted/Complete
[0.011s][info][gc,init] Address Space Size: 128M x 3 = 384M
[0.011s][info][gc,init] Heap Backing File: /memfd:java_heap
[0.011s][info][gc,init] Heap Backing Filesystem: tmpfs (0x1021994)
[0.011s][info][gc,init] Min Capacity: 8M
[0.011s][info][gc,init] Initial Capacity: 8M
[0.011s][info][gc,init] Max Capacity: 8M
[0.011s][info][gc,init] Max Reserve: 2M
[0.011s][info][gc,init] Pre-touch: Disabled
[0.011s][info][gc,init] Available space on backing filesystem: N/A
[0.013s][info][gc,init] Uncommit: Disabled
[0.071s][info][gc,init] Runtime Workers: 1 parallel
[0.072s][info][gc ] Using The Z Garbage Collector
[0.317s][info][gc,heap] GC(0) Min Capacity: 8M(100%)
[0.317s][info][gc,heap] GC(0) Max Capacity: 8M(100%)
<snip>

[0.902s][info][gc ] Allocation Stall (Unknown thread) 9.043ms
[0.916s][info][gc,heap] GC(21) Min Capacity: 8M(100%)
[0.916s][info][gc,heap] GC(21) Max Capacity: 8M(100%)
[0.916s][info][gc,heap] GC(21) Soft Max Capacity: 8M(100%)
[0.916s][info][gc,heap] GC(21) Mark Start Mark End Relocate Start Relocate End High Low
[0.916s][info][gc,heap] GC(21) Capacity: 8M (100%) 8M (100%) 8M (100%) 8M (100%) 8M (100%) 8M (100%)
[0.916s][info][gc,heap] GC(21) Reserve: 0M (0%) 0M (0%) 0M (0%) 0M (0%) 0M (0%) 0M (0%)
[0.916s][info][gc,heap] GC(21) Free: 0M (0%) 0M (0%) 0M (0%) 0M (0%) 0M (0%) 0M (0%)
[0.916s][info][gc,heap] GC(21) Used: 8M (100%) 8M (100%) 8M (100%) 8M (100%) 8M (100%) 8M (100%)
[0.916s][info][gc,heap] GC(21) Live: - 1M (15%) 1M (15%) 1M (15%) - -
[0.916s][info][gc,heap] GC(21) Allocated: - 0M (0%) 0M (0%) 0M (0%) - -
[0.916s][info][gc,heap] GC(21) Garbage: - 6M (85%) 6M (85%) 6M (85%) - -
[0.916s][info][gc,heap] GC(21) Reclaimed: - - 0M (0%) 0M (0%) - -
[0.916s][info][gc ] GC(21) Garbage Collection (Allocation Stall) 8M(100%)->8M(100%)
[0.916s][info][gc ] Allocation Stall (Unknown thread) 13.431ms
[0.916s][info][gc ] Out Of Memory (Unknown thread)
----------System.err:(4/200)----------

Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "MainThread"

Exception: java.lang.OutOfMemoryError thrown from the UncaughtExceptionHandler in thread "main"
----------rerun:(35/5661)*----------