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

Kees Cook
2020-06-29T06:18:25Z

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@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