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: 0887a7ebc9 ("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>
This commit is contained in:
Kees Cook 2020-05-07 18:36:23 -07:00 committed by Linus Torvalds
parent 17e34526f0
commit 8d58f222e8
2 changed files with 7 additions and 11 deletions

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@ -60,17 +60,14 @@ config UBSAN_SANITIZE_ALL
Enabling this option will get kernel image size increased Enabling this option will get kernel image size increased
significantly. significantly.
config UBSAN_NO_ALIGNMENT
bool "Disable checking of pointers alignment"
default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
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
accesses may produce a lot of false positives.
config UBSAN_ALIGNMENT config UBSAN_ALIGNMENT
def_bool !UBSAN_NO_ALIGNMENT bool "Enable checks for pointers alignment"
default !HAVE_EFFICIENT_UNALIGNED_ACCESS
depends on !X86 || !COMPILE_TEST
help
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 TEST_UBSAN config TEST_UBSAN
tristate "Module for testing for undefined behavior detection" tristate "Module for testing for undefined behavior detection"

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@ -25,7 +25,6 @@ CONFIG_KASAN=y
CONFIG_KASAN_INLINE=y CONFIG_KASAN_INLINE=y
CONFIG_UBSAN=y CONFIG_UBSAN=y
CONFIG_UBSAN_SANITIZE_ALL=y CONFIG_UBSAN_SANITIZE_ALL=y
CONFIG_UBSAN_NO_ALIGNMENT=y
CONFIG_UBSAN_NULL=y CONFIG_UBSAN_NULL=y
CONFIG_DEBUG_KMEMLEAK=y CONFIG_DEBUG_KMEMLEAK=y
CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=8192 CONFIG_DEBUG_KMEMLEAK_EARLY_LOG_SIZE=8192