On 25/06/2025 at 08:19, Sean Christopherson wrote:

Rename is_signed_type() to is_signed_var() to avoid colliding with a macro of the same name defined by linux/overflow.h. Note, overflow.h's version takes a type as the input, whereas the harness's version takes a variable!

This fixes warnings (and presumably potential test failures) in tests that utilize the selftests harness and happen to (indirectly) include overflow.h.

In file included from tools/include/linux/bits.h:34, from tools/include/linux/bitops.h:14, from tools/include/linux/hashtable.h:13, from include/kvm_util.h:11, from x86/userspace_msr_exit_test.c:11: tools/include/linux/overflow.h:31:9: error: "is_signed_type" redefined [-Werror] 31 | #define is_signed_type(type) (((type)(-1)) < (type)1) | ^~~~~~~~~~~~~~ In file included from include/kvm_test_harness.h:11, from x86/userspace_msr_exit_test.c:9: ../kselftest_harness.h:754:9: note: this is the location of the previous definition 754 | #define is_signed_type(var) (!!(((__typeof__(var))(-1)) < (__typeof__(var))1)) | ^~~~~~~~~~~~~~

Opportunistically use is_signed_type() to implement is_signed_var() so that the relationship and differences are obvious.

Fixes: fc92099902fb ("tools headers: Synchronize linux/bits.h with the kernel sources") Cc: Vincent Mailhol mailhol.vincent@wanadoo.fr Cc: Arnaldo Carvalho de Melo acme@redhat.com Signed-off-by: Sean Christopherson seanjc@google.com

---

This is probably compile-tested only, I don't think any of the KVM selftests utilize the harness's EXPECT macros.

tools/testing/selftests/kselftest_harness.h | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/kselftest_harness.h b/tools/testing/selftests/kselftest_harness.h index 2925e47db995..f3e7a46345db 100644 --- a/tools/testing/selftests/kselftest_harness.h +++ b/tools/testing/selftests/kselftest_harness.h @@ -56,6 +56,7 @@ #include <asm/types.h> #include <ctype.h> #include <errno.h> +#include <linux/overflow.h> #include <linux/unistd.h> #include <poll.h> #include <stdbool.h> @@ -751,7 +752,7 @@ for (; _metadata->trigger; _metadata->trigger = \ __bail(_assert, _metadata)) -#define is_signed_type(var) (!!(((__typeof__(var))(-1)) < (__typeof__(var))1)) +#define is_signed_var(var) is_signed_type(__typeof__(var))

It would potentially make sense to add the is_signed_var() to overflow.h. I see a couple places doing some is_signed_type(typeof(x)):

$ git grep "is_signed_type(typeof" | wc -l 5

And I can imagine this number growing in the future.

But this is by no way a reason strong enough to block this patch. It is just a random idea I am sharing here.

So that said:

Reviewed-by: Vincent Mailhol mailhol.vincent@wanadoo.fr

#define __EXPECT(_expected, _expected_str, _seen, _seen_str, _t, _assert) do { \ /* Avoid multiple evaluation of the cases */ \ @@ -759,7 +760,7 @@ __typeof__(_seen) __seen = (_seen); \ if (!(__exp _t __seen)) { \ /* Report with actual signedness to avoid weird output. */ \

• switch (is_signed_type(__exp) * 2 + is_signed_type(__seen)) { \
  

• switch (is_signed_var(__exp) * 2 + is_signed_var(__seen)) { \
  

  case 0: { \ uintmax_t __exp_print = (uintmax_t)__exp; \ uintmax_t __seen_print = (uintmax_t)__seen; \

base-commit: 78f4e737a53e1163ded2687a922fce138aee73f5

Yours sincerely, Vincent Mailhol