[PATCH v4 02/17] vmlinux.lds.h: Avoid KASAN and KCSAN's unwanted sections

[Kees Cook]

KASAN (-fsanitize=kernel-address) and KCSAN (-fsanitize=thread) produce
unwanted[1] .eh_frame and .init_array.* sections. Add them to DISCARDS,
except with CONFIG_CONSTRUCTORS, which wants to keep .init_array.*
sections.

[1] https://bugs.llvm.org/show_bug.cgi?id=46478

Signed-off-by: Kees Cook <keescook at chromium.org>
---
 include/asm-generic/vmlinux.lds.h | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 1248a206be8d..e53a2d4f47f6 100644
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -927,10 +927,30 @@
 	EXIT_DATA
 #endif
 
+/*
+ * Clang's -fsanitize=kernel-address and -fsanitize=thread produce
+ * unwanted sections (.eh_frame and .init_array.*), but
+ * CONFIG_CONSTRUCTORS wants to keep any .init_array.* sections.
+ * https://bugs.llvm.org/show_bug.cgi?id=46478
+ */
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KCSAN)
+# ifdef CONFIG_CONSTRUCTORS
+#  define KASAN_DISCARDS						\
+	*(.eh_frame)
+# else
+#  define KASAN_DISCARDS						\
+	*(.init_array) *(.init_array.*)					\
+	*(.eh_frame)
+# endif
+#else
+# define KASAN_DISCARDS
+#endif
+
 #define DISCARDS							\
 	/DISCARD/ : {							\
 	EXIT_DISCARDS							\
 	EXIT_CALL							\
+	KASAN_DISCARDS							\
 	*(.discard)							\
 	*(.discard.*)							\
 	*(.modinfo)							\
-- 
2.25.1