When compiling the pointer masking tests with -Wall this warning is present:

pointer_masking.c: In function ‘test_tagged_addr_abi_sysctl’: pointer_masking.c:203:9: warning: ignoring return value of ‘pwrite’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 203 | pwrite(fd, &value, 1, 0); | ^~~~~~~~~~~~~~~~~~~~~~~~ pointer_masking.c:208:9: warning: ignoring return value of ‘pwrite’ declared with attribute ‘warn_unused_result’ [-Wunused-result] 208 | pwrite(fd, &value, 1, 0);

I came across this on riscv64-linux-gnu-gcc (Ubuntu 11.4.0-1ubuntu1~22.04).

Fix this by checking that the number of bytes written equal the expected number of bytes written.

Fixes: 7470b5afd150 ("riscv: selftests: Add a pointer masking test") Signed-off-by: Charlie Jenkins charlie@rivosinc.com --- tools/testing/selftests/riscv/abi/pointer_masking.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c index dee41b7ee3e3..5ae941e9ac73 100644 --- a/tools/testing/selftests/riscv/abi/pointer_masking.c +++ b/tools/testing/selftests/riscv/abi/pointer_masking.c @@ -189,6 +189,7 @@ static void test_tagged_addr_abi_sysctl(void) { char value; int fd; + int ret;

ksft_print_msg("Testing tagged address ABI sysctl\n");

@@ -200,14 +201,24 @@ static void test_tagged_addr_abi_sysctl(void) }

value = '1'; - pwrite(fd, &value, 1, 0); + ret = pwrite(fd, &value, 1, 0); + if (ret != 1) { + ksft_test_result_fail("Write to /proc/sys/abi/tagged_addr_disabled failed.\n"); + return; + } + ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL, "sysctl disabled\n");

value = '0'; - pwrite(fd, &value, 1, 0); - ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0, - "sysctl enabled\n"); + ret = pwrite(fd, &value, 1, 0); + if (ret != 2) { + ksft_test_result_fail("Write to /proc/sys/abi/tagged_addr_disabled failed.\n"); + return; + } + + ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL, + "sysctl disabled\n");

set_tagged_addr_ctrl(0, false);

--- base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37 change-id: 20241204-fix_warnings_pointer_masking_tests-3860e4f35429