Messages in this thread | | | From | David Gow <> | Date | Sat, 14 Jan 2023 12:31:51 +0800 | Subject | Re: [PATCH] kunit: memcpy: Split slow memcpy tests into MEMCPY_SLOW_KUNIT_TEST |
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On Sat, 14 Jan 2023 at 08:54, Kees Cook <keescook@chromium.org> wrote: > > Since the long memcpy tests may stall a system for tens of seconds > in virtualized architecture environments, split those tests off under > CONFIG_MEMCPY_SLOW_KUNIT_TEST so they can be separately disabled. > > Reported-by: Guenter Roeck <linux@roeck-us.net> > Link: https://lore.kernel.org/lkml/20221226195206.GA2626419@roeck-us.net > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Reviewed-and-tested-by: Guenter Roeck <linux@roeck-us.net> > Reviewed-by: David Gow <davidgow@google.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Nathan Chancellor <nathan@kernel.org> > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Kees Cook <keescook@chromium.org> > ---
Thanks: this is okay as-is, but I left a few suggestions below, having tried it out a bit more.
Daniel's comment about kunit_skip() aborting the test is the only real fix, but depending on how easy you'd want to make turning these tests off, there are a couple of possible tweaks to the Kconfig option.
Cheers, -- David
> v2: fix tristate to bool > v1: https://lore.kernel.org/lkml/20230107040203.never.112-kees@kernel.org > --- > lib/Kconfig.debug | 9 +++++++++ > lib/memcpy_kunit.c | 15 ++++++++++++--- > 2 files changed, 21 insertions(+), 3 deletions(-) > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index c2c78d0e761c..f90637171453 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -2621,6 +2621,15 @@ config MEMCPY_KUNIT_TEST > > If unsure, say N. > > +config MEMCPY_SLOW_KUNIT_TEST > + bool "Include exhaustive memcpy tests" if !KUNIT_ALL_TESTS
I think it'd be better to not include the "if !KUNIT_ALL_TESTS" here, because it's very convenient to be able to use: ./tools/testing/kunit/kunit.py run memcpy --kconfig_add CONFIG_MEMCPY_SLOW_KUNIT_TEST=n to override it.
That does undermine the way KUNIT_ALL_TESTS works a bit, though it depends if you want to consider this a new set of tests, or just an option for the existing ones.
> + depends on MEMCPY_KUNIT_TEST > + default KUNIT_ALL_TESTS
Does this default work for everyone? Personally, I think these tests aren't slow enough that we'd want them disabled from an "all tests" build by default. So I'd keep it as-is.
> + help > + Some memcpy tests are quite exhaustive in checking for overlaps > + and bit ranges. These can be very slow, so they are split out > + as a separate config. > + > config IS_SIGNED_TYPE_KUNIT_TEST > tristate "Test is_signed_type() macro" if !KUNIT_ALL_TESTS > depends on KUNIT > diff --git a/lib/memcpy_kunit.c b/lib/memcpy_kunit.c > index 89128551448d..5a545e1b5dbb 100644 > --- a/lib/memcpy_kunit.c > +++ b/lib/memcpy_kunit.c > @@ -307,8 +307,12 @@ static void set_random_nonzero(struct kunit *test, u8 *byte) > } > } > > -static void init_large(struct kunit *test) > +static int init_large(struct kunit *test) > { > + if (!IS_ENABLED(CONFIG_MEMCPY_SLOW_KUNIT_TEST)) { > + kunit_skip(test, "Slow test skipped. Enable with CONFIG_MEMCPY_SLOW_KUNIT_TEST=y"); > + return -EBUSY;
As Daniel notes, it shouldn't be necessary to return here, as kunit_skip() will abort the test. (It's a macro, so isn't marked __noreturn itself, but kunit_try_catch_throw(), which it uses, is.)
> + } > > /* Get many bit patterns. */ > get_random_bytes(large_src, ARRAY_SIZE(large_src)); > @@ -319,6 +323,8 @@ static void init_large(struct kunit *test) > > /* Explicitly zero the entire destination. */ > memset(large_dst, 0, ARRAY_SIZE(large_dst)); > + > + return 0; > } > > /* > @@ -327,7 +333,9 @@ static void init_large(struct kunit *test) > */ > static void copy_large_test(struct kunit *test, bool use_memmove) > { > - init_large(test); > + > + if (init_large(test)) > + return; > > /* Copy a growing number of non-overlapping bytes ... */ > for (int bytes = 1; bytes <= ARRAY_SIZE(large_src); bytes++) { > @@ -472,7 +480,8 @@ static void memmove_overlap_test(struct kunit *test) > static const int bytes_start = 1; > static const int bytes_end = ARRAY_SIZE(large_src) + 1; > > - init_large(test); > + if (init_large(test)) > + return; > > /* Copy a growing number of overlapping bytes ... */ > for (int bytes = bytes_start; bytes < bytes_end; > -- > 2.34.1 > [unhandled content-type:application/pkcs7-signature] | |