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-rw-r--r--lib/Kconfig.ubsan22
-rw-r--r--lib/Makefile2
2 files changed, 20 insertions, 4 deletions
diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 0e04fcb3ab3d..9deb655838b0 100644
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -5,11 +5,25 @@ config ARCH_HAS_UBSAN_SANITIZE_ALL
 config UBSAN
 	bool "Undefined behaviour sanity checker"
 	help
-	  This option enables undefined behaviour sanity checker
+	  This option enables the Undefined Behaviour sanity checker.
 	  Compile-time instrumentation is used to detect various undefined
-	  behaviours in runtime. Various types of checks may be enabled
-	  via boot parameter ubsan_handle
-	  (see: Documentation/dev-tools/ubsan.rst).
+	  behaviours at runtime. For more details, see:
+	  Documentation/dev-tools/ubsan.rst
+
+config UBSAN_TRAP
+	bool "On Sanitizer warnings, abort the running kernel code"
+	depends on UBSAN
+	depends on $(cc-option, -fsanitize-undefined-trap-on-error)
+	help
+	  Building kernels with Sanitizer features enabled tends to grow
+	  the kernel size by around 5%, due to adding all the debugging
+	  text on failure paths. To avoid this, Sanitizer instrumentation
+	  can just issue a trap. This reduces the kernel size overhead but
+	  turns all warnings (including potentially harmless conditions)
+	  into full exceptions that abort the running kernel code
+	  (regardless of context, locks held, etc), which may destabilize
+	  the system. For some system builders this is an acceptable
+	  trade-off.
 
 config UBSAN_SANITIZE_ALL
 	bool "Enable instrumentation for the entire kernel"
diff --git a/lib/Makefile b/lib/Makefile
index 3fc06399295d..685aee60de1d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -286,7 +286,9 @@ quiet_cmd_build_OID_registry = GEN     $@
 clean-files	+= oid_registry_data.c
 
 obj-$(CONFIG_UCS2_STRING) += ucs2_string.o
+ifneq ($(CONFIG_UBSAN_TRAP),y)
 obj-$(CONFIG_UBSAN) += ubsan.o
+endif
 
 UBSAN_SANITIZE_ubsan.o := n
 KASAN_SANITIZE_ubsan.o := n