ubsan: disable UBSAN_ALIGNMENT under COMPILE_TEST

The documentation for UBSAN_ALIGNMENT already mentions that it should
not be used on all*config builds (and for efficient-unaligned-access
architectures), so just refactor the Kconfig to correctly implement this
so randconfigs will stop creating insane images that freak out objtool
under CONFIG_UBSAN_TRAP (due to the false positives producing functions
that never return, etc).

Link: http://lkml.kernel.org/r/202005011433.C42EA3E2D@keescook
Fixes: 0887a7ebc977 ("ubsan: add trap instrumentation option")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lore.kernel.org/linux-next/202004231224.D6B3B650@keescook/
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/Kconfig.ubsan b/lib/Kconfig.ubsan
index 48469c95d78e6da6c0656502c6d11b1216cef3c9..929211039bacd0c0d4ccd2aa7af0a9c69744132f 100644 (file)
--- a/lib/Kconfig.ubsan
+++ b/lib/Kconfig.ubsan
@@ -60,18 +60,15 @@ config UBSAN_SANITIZE_ALL
          Enabling this option will get kernel image size increased
          significantly.
 
-config UBSAN_NO_ALIGNMENT
-       bool "Disable checking of pointers alignment"
-       default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
+config UBSAN_ALIGNMENT
+       bool "Enable checks for pointers alignment"
+       default !HAVE_EFFICIENT_UNALIGNED_ACCESS
+       depends on !X86 || !COMPILE_TEST
        help
-         This option disables the check of unaligned memory accesses.
-         This option should be used when building allmodconfig.
-         Disabling this option on architectures that support unaligned
+         This option enables the check of unaligned memory accesses.
+         Enabling this option on architectures that support unaligned
          accesses may produce a lot of false positives.
 
-config UBSAN_ALIGNMENT
-       def_bool !UBSAN_NO_ALIGNMENT
-
 config TEST_UBSAN
        tristate "Module for testing for undefined behavior detection"
        depends on m

diff --git a/tools/testing/selftests/wireguard/qemu/debug.config b/tools/testing/selftests/wireguard/qemu/debug.config
index 5909e7ef2a5c5c1a30b40e4c7d58ff585335e756..9803dbb54181ce8cac6111d83b8c36c58331d959 100644 (file)
--- a/tools/testing/selftests/wireguard/qemu/debug.config
+++ b/tools/testing/selftests/wireguard/qemu/debug.config
@@ -25,7 +25,6 @@ CONFIG_KASAN=y
 CONFIG_KASAN_INLINE=y
 CONFIG_UBSAN=y
 CONFIG_UBSAN_SANITIZE_ALL=y
-CONFIG_UBSAN_NO_ALIGNMENT=y
 CONFIG_UBSAN_NULL=y
 CONFIG_DEBUG_KMEMLEAK=y
 CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=8192