G1: SIGSEGV in java.lang.String.getChars / ~RuntimeStub::_slow_arraycopy_Java / slow_arraycopy_C

Application crashes after 25 hours (HS 19 b09, fastdebug, -XX:+UseG1GC -XX:+AggressiveOpts):

# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00002b7613585415, pid=29413, tid=1154545984
#

Stack: [0x0000000044c0f000,0x0000000044d10000], sp=0x0000000044d0d8f0, free space=1018k
Native frames: (J=compiled Java code, j=interpreted, Vv=VM code, C=native code)
V [libjvm.so+0xa86415];; SharedRuntime::slow_arraycopy_C(oopDesc*, int, oopDesc*, int, int, JavaThread*)+0x155

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
v ~RuntimeStub::_slow_arraycopy_Java
J java.lang.String.getChars(II[CI)V
J java.io.ObjectOutputStream.writeObject0(Ljava/lang/Object;Z)V
J java.io.ObjectOutputStream.writeArray(Ljava/lang/Object;Ljava/io/ObjectStreamClass;Z)V
...