-current build failure

 Seeing this for r:238655

===> dtrace/dtrace (depend)
_at_ -> /usr/src/sys
machine -> /usr/src/sys/amd64/include
x86 -> /usr/src/sys/x86/include
awk -f _at_/tools/makeobjops.awk _at_/kern/bus_if.m -h
awk -f _at_/tools/makeobjops.awk _at_/kern/device_if.m -h
awk -f _at_/tools/vnode_if.awk _at_/kern/vnode_if.src -p
awk -f _at_/tools/vnode_if.awk _at_/kern/vnode_if.src -q
awk -f _at_/tools/vnode_if.awk _at_/kern/vnode_if.src -h
ln -sf /usr/obj/usr/src/sys/hyster3/opt_compat.h opt_compat.h
ln -sf /usr/obj/usr/src/sys/hyster3/opt_kstack_pages.h opt_kstack_pages.h
ln -sf /usr/obj/usr/src/sys/hyster3/opt_nfs.h opt_nfs.h
ln -sf /usr/obj/usr/src/sys/hyster3/opt_hwpmc_hooks.h opt_hwpmc_hooks.h
clang -c -O2 -pipe -DDIS_MEM -DSMP -DDEBUG -fno-strict-aliasing
-Werror -D_KERNEL -DKLD_MODULE -nostdinc
-I/usr/src/sys/modules/dtrace/dtrace/../../../cddl/contrib/opensolaris/uts/intel
-I/usr/src/sys/modules/dtrace/dtrace/../../../cddl/compat/opensolaris
-I/usr/src/sys/modules/dtrace/dtrace/../../../cddl/dev/dtrace
-I/usr/src/sys/modules/dtrace/dtrace/../../../cddl/dev/dtrace/amd64
-I/usr/src/sys/modules/dtrace/dtrace/../../../cddl/contrib/opensolaris/uts/common
-I/usr/src/sys/modules/dtrace/dtrace/../../..
-DHAVE_KERNEL_OPTION_HEADERS -include
/usr/obj/usr/src/sys/hyster3/opt_global.h -I. -I_at_ -I_at_/contrib/altq -g
-fno-omit-frame-pointer -I/usr/obj/usr/src/sys/hyster3 -mno-aes
-mno-avx -mcmodel=kernel -mno-red-zone -mno-mmx -mno-sse -msoft-float
-fno-asynchronous-unwind-tables -ffreestanding -fstack-protector
-std=iso9899:1999 -Qunused-arguments -fstack-protector -Wall
-Wredundant-decls -Wnested-externs -Wstrict-prototypes
-Wmissing-prototypes -Wpointer-arith -Winline -Wcast-qual -Wundef
-Wno-pointer-sign -fformat-extensions -Wmissing-include-dirs
-fdiagnostics-show-option -Wno-error-tautological-compare
-Wno-error-empty-body -Wno-error-parentheses-equality
-Wno-unknown-pragmas  _at_/amd64/amd64/genassym.c
In file included from _at_/amd64/amd64/genassym.c:46:
In file included from /usr/src/sys/modules/dtrace/dtrace/../../../sys/buf.h:262:
In file included from
/usr/src/sys/modules/dtrace/dtrace/../../../cddl/compat/opensolaris/sys/proc.h:34:
In file included from /usr/src/sys/modules/dtrace/dtrace/../../../sys/proc.h:62:
In file included from
/usr/src/sys/modules/dtrace/dtrace/../../../cddl/compat/opensolaris/sys/pcpu.h:33:
In file included from /usr/src/sys/modules/dtrace/dtrace/../../../sys/pcpu.h:44:
./machine/pcpu.h:226:13: error: indirection of non-volatile null
pointer will be deleted, not trap
      [-Werror,-Wnull-dereference]
            : "m" (*(char *)OFFSETOF_CURTHREAD));
                   ^~~~~~~~~~~~~~~~~~~~~~~~~~~
./machine/pcpu.h:226:13: note: consider using __builtin_trap() or
qualifying pointer with 'volatile'
1 error generated.
*** [genassym.o] Error code 1

Stop in /usr/src/sys/modules/dtrace/dtrace.
*** [depend] Error code 1


thanks
-kim