From 924cf780a23a6c01638ee9865dcd63eb21c72b4a Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Sun, 7 Apr 2024 19:56:03 +0200
Subject: [PATCH] Fix GENERIC-KASAN kernel build for amd64

Work around https://github.com/llvm/llvm-project/issues/87923, which
leads to an assertion failure compiling several kernel source files with
asan enabled.

PR:		276104
MFC after:	1 month

(cherry picked from commit b811dac2115a6ada606c03d7d823a95d11c5f3c9)
---
 sys/conf/kern.pre.mk | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/conf/kern.pre.mk b/sys/conf/kern.pre.mk
index 6bf647f5c3e..567c68e5887 100644
--- a/sys/conf/kern.pre.mk
+++ b/sys/conf/kern.pre.mk
@@ -111,6 +111,11 @@ SAN_CFLAGS+=	-DSAN_NEEDS_INTERCEPTORS -DSAN_INTERCEPTOR_PREFIX=kasan \
 #	upstreamed similar to: https://reviews.llvm.org/D98285
 #
 SAN_CFLAGS+=	-mllvm -asan-mapping-offset=0xdfff208000000000
+.elif ${MACHINE_CPUARCH} == "amd64" && \
+      ${COMPILER_TYPE} == "clang" && ${COMPILER_VERSION} >= 180000
+# Work around https://github.com/llvm/llvm-project/issues/87923, which leads to
+# an assertion failure compiling dtrace.c with asan enabled.
+SAN_CFLAGS+=	-mllvm -asan-use-stack-safety=0
 .endif
 .endif