The patch titled
Subject: lib/ubsan: default UBSAN_ALIGNMENT to not set
has been added to the -mm tree. Its filename is
lib-ubsan-default-ubsan_alignment-to-not-set.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-ubsan-default-ubsan_alignment-to-not-set.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-ubsan-default-ubsan_alignment-to-not-set.patch
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------------------------------------------------------
From: Anders Roxell <anders.roxell@xxxxxxxxxx>
Subject: lib/ubsan: default UBSAN_ALIGNMENT to not set
When booting an allmodconfig kernel, there are a lot of false-positives.
With a message like this 'UBSAN: Undefined behaviour in...' with a call
trace that follows.
Reworked so that when building a allmodconfig kernel that turns everything
into '=m' or '=y' will turn off UBSAN_ALIGNMENT.
Link: http://lkml.kernel.org/r/20181217150326.30933-1-anders.roxell@xxxxxxxxxx
Signed-off-by: Anders Roxell <anders.roxell@xxxxxxxxxx>
Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
Acked-by: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/Kconfig.ubsan | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
--- a/lib/Kconfig.ubsan~lib-ubsan-default-ubsan_alignment-to-not-set
+++ a/lib/Kconfig.ubsan
@@ -27,15 +27,19 @@ config UBSAN_SANITIZE_ALL
Enabling this option will get kernel image size increased
significantly.
-config UBSAN_ALIGNMENT
- bool "Enable checking of pointers alignment"
+config UBSAN_NO_ALIGNMENT
+ bool "Disable checking of pointers alignment"
depends on UBSAN
- default y if !HAVE_EFFICIENT_UNALIGNED_ACCESS
+ default y if HAVE_EFFICIENT_UNALIGNED_ACCESS
help
- This option enables detection of unaligned memory accesses.
- Enabling this option on architectures that support unaligned
+ 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
+ def_bool !UBSAN_NO_ALIGNMENT
+
config TEST_UBSAN
tristate "Module for testing for undefined behavior detection"
depends on m && UBSAN
_
Patches currently in -mm which might be from anders.roxell@xxxxxxxxxx are
kasan-mark-file-common-so-ftrace-doesnt-trace-it.patch
lib-ubsan-default-ubsan_alignment-to-not-set.patch
