Some tests with enabled logging start crash with SEGV.
Failure is reproduced by running test gc/stress/gcbasher/TestGCBasherWithG1.java with "-Xlog:all=trace:file=all.log"

the stacktrace:

--------------- T H R E A D ---------------

Current thread (0x00007ff484009800): VMThread "VM Thread" [stack: 0x00007000083ac000,0x00007000084ac000] [id=13827]

Stack: [0x00007000083ac000,0x00007000084ac000], sp=0x00007000084aa5f0, free space=1017k
Native frames: (J=compiled Java code, A=aot compiled Java code, j=interpreted, Vv=VM code, C=native code)
C [libsystem_platform.dylib+0x1460] _platform_memmove$VARIANT$Nehalem+0x60
C [libsystem_c.dylib+0x3e8eb] __sfvwrite+0x173
C [libsystem_c.dylib+0x485ff] __vfprintf+0x3de5
C [libsystem_c.dylib+0x6d059] __v2printf+0x1d9
C [libsystem_c.dylib+0x5234b] _vsnprintf+0x19f
C [libsystem_c.dylib+0x523fe] vsnprintf+0x50
V [libjvm.dylib+0xa368bc] os::vsnprintf(char*, unsigned long, char const*, __va_list_tag*)+0x12
V [libjvm.dylib+0xa39841] outputStream::do_vsnprintf(char*, unsigned long, char const*, __va_list_tag*, bool, unsigned long&)+0xb1
V [libjvm.dylib+0xa39a71] outputStream::do_vsnprintf_and_write(char const*, __va_list_tag*, bool)+0x61
V [libjvm.dylib+0xa39bbf] outputStream::print_cr(char const*, ...)+0x81
V [libjvm.dylib+0x536e6b] G1PrintCollectionSetClosure::do_heap_region(HeapRegion*)+0x11b
V [libjvm.dylib+0x535864] G1CollectionSet::iterate_from(HeapRegionClosure*, unsigned int, unsigned int) const+0x54
V [libjvm.dylib+0x52a2d2] G1CollectedHeap::do_collection_pause_at_safepoint(double)+0x7f2
V [libjvm.dylib+0xc8e4a2] VM_G1CollectForAllocation::doit()+0xd4
V [libjvm.dylib+0xc8cc37] VM_Operation::evaluate()+0x10f
V [libjvm.dylib+0xc8b943] VMThread::evaluate_operation(VM_Operation*)+0x11b
V [libjvm.dylib+0xc8b298] VMThread::loop()+0x18c
V [libjvm.dylib+0xc8afd4] VMThread::run()+0xce
V [libjvm.dylib+0xa2e644] thread_native_entry(Thread*)+0x145
C [libsystem_pthread.dylib+0x3661] _pthread_body+0x154
C [libsystem_pthread.dylib+0x350d] _pthread_body+0x0
C [libsystem_pthread.dylib+0x2bf9] thread_start+0xd