diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -94,13 +94,15 @@
 KASAN_ENABLED!=	grep KASAN opt_global.h || true ; echo
 .if !empty(KASAN_ENABLED)
 SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kasan \
-		-fsanitize=kernel-address \
-		-mllvm -asan-stack=true \
+		-fsanitize=kernel-address
+.if ${COMPILER_TYPE} == "clang"
+SAN_CFLAGS+=	-mllvm -asan-stack=true \
 		-mllvm -asan-instrument-dynamic-allocas=true \
 		-mllvm -asan-globals=true \
 		-mllvm -asan-use-after-scope=true \
 		-mllvm -asan-instrumentation-with-call-threshold=0 \
 		-mllvm -asan-instrument-byval=false
+.endif
 
 .if ${MACHINE_CPUARCH} == "aarch64"
 # KASAN/ARM64 TODO: -asan-mapping-offset is calculated from:
@@ -110,7 +112,11 @@
 #	KASAN_MIN_ADDRESS, and this offset value should eventually be
 #	upstreamed similar to: https://reviews.llvm.org/D98285
 #
+.if ${COMPILER_TYPE} == "clang"
 SAN_CFLAGS+=	-mllvm -asan-mapping-offset=0xdfff208000000000
+.else
+SAN_CFLAGS+=	-fasan-shadow-offset=0xdfff208000000000
+.endif
 .elif ${MACHINE_CPUARCH} == "amd64" && \
       ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 180000
 # Work around https://github.com/llvm/llvm-project/issues/87923, which leads to