ubsan: allow to disable the null sanitizer

Some architectures use a hardware defined structure at address zero. Checking for a null pointer will result in many ubsan reports. Allow users to disable the null sanitizer. Signed-off-by: Christian Borntraeger <[email protected]> Acked-by: Andrey Ryabinin <[email protected]> Signed-off-by: Heiko Carstens <[email protected]> Signed-off-by: Martin Schwidefsky <[email protected]>
josf · Sep 20, 2016 · 725c4d2 · 725c4d2
1 parent f296190
commit 725c4d2
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diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
@@ -1,6 +1,9 @@
 config ARCH_HAS_UBSAN_SANITIZE_ALL
 	bool
 
+config ARCH_WANTS_UBSAN_NO_NULL
+	def_bool n
+
 config UBSAN
 	bool "Undefined behaviour sanity checker"
 	help
@@ -34,3 +37,11 @@ config UBSAN_ALIGNMENT
 	  This option enables detection of unaligned memory accesses.
 	  Enabling this option on architectures that support unaligned
 	  accesses may produce a lot of false positives.
+
+config UBSAN_NULL
+	bool "Enable checking of null pointers"
+	depends on UBSAN
+	default y if !ARCH_WANTS_UBSAN_NO_NULL
+	help
+	  This option enables detection of memory accesses via a
+	  null pointer.
diff --git a/scripts/Makefile.ubsan b/scripts/Makefile.ubsan
@@ -3,7 +3,6 @@ ifdef CONFIG_UBSAN
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=integer-divide-by-zero)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=unreachable)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=vla-bound)
-      CFLAGS_UBSAN += $(call cc-option, -fsanitize=null)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=signed-integer-overflow)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=bounds)
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=object-size)
@@ -14,4 +13,8 @@ ifdef CONFIG_UBSAN
 ifdef CONFIG_UBSAN_ALIGNMENT
       CFLAGS_UBSAN += $(call cc-option, -fsanitize=alignment)
 endif
+
+ifdef CONFIG_UBSAN_NULL
+      CFLAGS_UBSAN += $(call cc-option, -fsanitize=null)
+endif
 endif