selftests: arm64: Check fread return value in exec_target

Fix -Wunused-result warning generated when compiled with gcc 13.3.0,
by checking fread's return value and handling errors, preventing
potential failures when reading from stdin.

Fixes compiler warning:
warning: ignoring return value of 'fread' declared with attribute
'warn_unused_result' [-Wunused-result]

Fixes: 806a15b2545e ("kselftests/arm64: add PAuth test for whether exec() changes keys")
Signed-off-by: Bala-Vignesh-Reddy <reddybalavignesh9979@gmail.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/tools/testing/selftests/arm64/pauth/exec_target.c b/tools/testing/selftests/arm64/pauth/exec_target.c
index 4435600ca400dd9f500fc4271b985d65ba4e5429..e597861b26d6bf3e3141eded6d1dafe99b8d5a34 100644 (file)
--- a/tools/testing/selftests/arm64/pauth/exec_target.c
+++ b/tools/testing/selftests/arm64/pauth/exec_target.c
@@ -13,7 +13,12 @@ int main(void)
        unsigned long hwcaps;
        size_t val;
 
-       fread(&val, sizeof(size_t), 1, stdin);
+       size_t size = fread(&val, sizeof(size_t), 1, stdin);
+
+       if (size != 1) {
+               fprintf(stderr, "Could not read input from stdin\n");
+               return EXIT_FAILURE;
+       }
 
        /* don't try to execute illegal (unimplemented) instructions) caller
         * should have checked this and keep worker simple