On Wed, Jul 13, 2022 at 12:04 PM Marco Elver <elver@xxxxxxxxxx> wrote: > > On Fri, Jul 01, 2022 at 04:22PM +0200, 'Alexander Potapenko' via kasan-dev wrote: > [...] > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 2e24db4bff192..59819e6fa5865 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -963,6 +963,7 @@ config DEBUG_STACKOVERFLOW > > > > source "lib/Kconfig.kasan" > > source "lib/Kconfig.kfence" > > +source "lib/Kconfig.kmsan" > > > > endmenu # "Memory Debugging" > > > > diff --git a/lib/Kconfig.kmsan b/lib/Kconfig.kmsan > > new file mode 100644 > > index 0000000000000..8f768d4034e3c > > --- /dev/null > > +++ b/lib/Kconfig.kmsan > > @@ -0,0 +1,50 @@ > > +# SPDX-License-Identifier: GPL-2.0-only > > +config HAVE_ARCH_KMSAN > > + bool > > + > > +config HAVE_KMSAN_COMPILER > > + # Clang versions <14.0.0 also support -fsanitize=kernel-memory, but not > > + # all the features necessary to build the kernel with KMSAN. > > + depends on CC_IS_CLANG && CLANG_VERSION >= 140000 > > + def_bool $(cc-option,-fsanitize=kernel-memory -mllvm -msan-disable-checks=1) > > + > > +config HAVE_KMSAN_PARAM_RETVAL > > + # Separate check for -fsanitize-memory-param-retval support. > > This comment doesn't add much value, maybe instead say that "Supported > only by Clang >= 15." Fixed. > > + depends on CC_IS_CLANG && CLANG_VERSION >= 140000 > > Why not just "depends on HAVE_KMSAN_COMPILER"? (All > fsanitize-memory-param-retval supporting compilers must also be KMSAN > compilers.) Good idea, will do. > > + def_bool $(cc-option,-fsanitize=kernel-memory -fsanitize-memory-param-retval) > > + > > + > > HAVE_KMSAN_PARAM_RETVAL should be moved under "if KMSAN" so that this > isn't unnecessarily evaluated in every kernel build (saving 1 shelling > out to clang in most builds). Ack. > > +config KMSAN > > + bool "KMSAN: detector of uninitialized values use" > > + depends on HAVE_ARCH_KMSAN && HAVE_KMSAN_COMPILER > > + depends on SLUB && DEBUG_KERNEL && !KASAN && !KCSAN > > + select STACKDEPOT > > + select STACKDEPOT_ALWAYS_INIT > > + help > > + KernelMemorySanitizer (KMSAN) is a dynamic detector of uses of > > + uninitialized values in the kernel. It is based on compiler > > + instrumentation provided by Clang and thus requires Clang to build. > > + > > + An important note is that KMSAN is not intended for production use, > > + because it drastically increases kernel memory footprint and slows > > + the whole system down. > > + > > + See <file:Documentation/dev-tools/kmsan.rst> for more details. > > + > > +if KMSAN > > + > > +config KMSAN_CHECK_PARAM_RETVAL > > + bool "Check for uninitialized values passed to and returned from functions" > > + default HAVE_KMSAN_PARAM_RETVAL > > This can be enabled even if !HAVE_KMSAN_PARAM_RETVAL. Should this be: > > default y > depends on HAVE_KMSAN_PARAM_RETVAL > > instead? > Ack -- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Liana Sebastian Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
