kcsan: test: Initialize dummy variable

[PATCH] kcsan: test: Initialize dummy variable

Posted by Marco Elver 2 months, 2 weeks ago

Newer compiler versions rightfully point out:

 kernel/kcsan/kcsan_test.c:591:41: error: variable 'dummy' is
 uninitialized when passed as a const pointer argument here
 [-Werror,-Wuninitialized-const-pointer]
   591 |         KCSAN_EXPECT_READ_BARRIER(atomic_read(&dummy), false);
       |                                                ^~~~~
 1 error generated.

Although this particular test does not care about the value stored in
the dummy atomic variable, let's silence the warning.

Link: https://lkml.kernel.org/r/CA+G9fYu8JY=k-r0hnBRSkQQrFJ1Bz+ShdXNwC1TNeMt0eXaxeA@mail.gmail.com
Fixes: 8bc32b348178 ("kcsan: test: Add test cases for memory barrier instrumentation")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Marco Elver <elver@google.com>
---
 kernel/kcsan/kcsan_test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/kcsan/kcsan_test.c b/kernel/kcsan/kcsan_test.c
index c2871180edcc..49ab81faaed9 100644
--- a/kernel/kcsan/kcsan_test.c
+++ b/kernel/kcsan/kcsan_test.c
@@ -533,7 +533,7 @@ static void test_barrier_nothreads(struct kunit *test)
 	struct kcsan_scoped_access *reorder_access = NULL;
 #endif
 	arch_spinlock_t arch_spinlock = __ARCH_SPIN_LOCK_UNLOCKED;
-	atomic_t dummy;
+	atomic_t dummy = ATOMIC_INIT(0);
 
 	KCSAN_TEST_REQUIRES(test, reorder_access != NULL);
 	KCSAN_TEST_REQUIRES(test, IS_ENABLED(CONFIG_SMP));
-- 
2.50.0.727.gbf7dc18ff4-goog

Re: [PATCH] kcsan: test: Initialize dummy variable

Posted by Alexander Potapenko 2 months, 2 weeks ago

On Tue, Jul 22, 2025 at 8:39 PM Marco Elver <elver@google.com> wrote:
>
> Newer compiler versions rightfully point out:
>
>  kernel/kcsan/kcsan_test.c:591:41: error: variable 'dummy' is
>  uninitialized when passed as a const pointer argument here
>  [-Werror,-Wuninitialized-const-pointer]
>    591 |         KCSAN_EXPECT_READ_BARRIER(atomic_read(&dummy), false);
>        |                                                ^~~~~
>  1 error generated.
>
> Although this particular test does not care about the value stored in
> the dummy atomic variable, let's silence the warning.
>
> Link: https://lkml.kernel.org/r/CA+G9fYu8JY=k-r0hnBRSkQQrFJ1Bz+ShdXNwC1TNeMt0eXaxeA@mail.gmail.com
> Fixes: 8bc32b348178 ("kcsan: test: Add test cases for memory barrier instrumentation")
> Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
> Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>