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>
---
Changes in v4:
- Skip sysctl_enabled test if first pwrite failed
- Link to v3: https://lore.kernel.org/r/20241205-fix_warnings_pointer_masking_tests-v3-1-5c28b0f9640d@rivosinc.com

Changes in v3:
- Fix sysctl enabled test case (Drew/Alex)
- Move pwrite err condition into goto (Drew)
- Link to v2: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v2-1-1bf0c5095f58@rivosinc.com

Changes in v2:
- I had ret != 2 for testing, I changed it to be ret != 1.
- Link to v1: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v1-1-ea1e9665ce7a@rivosinc.com
---
 tools/testing/selftests/riscv/abi/pointer_masking.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c
index dee41b7ee3e3..759445d5f265 100644
--- a/tools/testing/selftests/riscv/abi/pointer_masking.c
+++ b/tools/testing/selftests/riscv/abi/pointer_masking.c
@@ -189,6 +189,8 @@ static void test_tagged_addr_abi_sysctl(void)
 {
 	char value;
 	int fd;
+	int ret;
+	char *err_pwrite_msg = "failed to write to /proc/sys/abi/tagged_addr_disabled\n";
 
 	ksft_print_msg("Testing tagged address ABI sysctl\n");
 
@@ -200,18 +202,32 @@ 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_skip(err_pwrite_msg);
+		goto err_pwrite;
+	}
+
 	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
 			 "sysctl disabled\n");
 
 	value = '0';
-	pwrite(fd, &value, 1, 0);
+	ret = pwrite(fd, &value, 1, 0);
+	if (ret != 1)
+		goto err_pwrite;
+
 	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0,
 			 "sysctl enabled\n");
 
 	set_tagged_addr_ctrl(0, false);
 
 	close(fd);
+
+	return;
+
+err_pwrite:
+	close(fd);
+	ksft_test_result_fail(err_pwrite_msg);
 }
 
 static void test_tagged_addr_abi_pmlen(int pmlen)

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

On Thu, Dec 05, 2024 at 01:49:31PM -0800, Charlie Jenkins wrote:
> 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>
> ---
> Changes in v4:
> - Skip sysctl_enabled test if first pwrite failed
> - Link to v3: https://lore.kernel.org/r/20241205-fix_warnings_pointer_masking_tests-v3-1-5c28b0f9640d@rivosinc.com
> 
> Changes in v3:
> - Fix sysctl enabled test case (Drew/Alex)
> - Move pwrite err condition into goto (Drew)
> - Link to v2: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v2-1-1bf0c5095f58@rivosinc.com
> 
> Changes in v2:
> - I had ret != 2 for testing, I changed it to be ret != 1.
> - Link to v1: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v1-1-ea1e9665ce7a@rivosinc.com
> ---
>  tools/testing/selftests/riscv/abi/pointer_masking.c | 20 ++++++++++++++++++--
>  1 file changed, 18 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c
> index dee41b7ee3e3..759445d5f265 100644
> --- a/tools/testing/selftests/riscv/abi/pointer_masking.c
> +++ b/tools/testing/selftests/riscv/abi/pointer_masking.c
> @@ -189,6 +189,8 @@ static void test_tagged_addr_abi_sysctl(void)
>  {
>  	char value;
>  	int fd;
> +	int ret;
> +	char *err_pwrite_msg = "failed to write to /proc/sys/abi/tagged_addr_disabled\n";
>  
>  	ksft_print_msg("Testing tagged address ABI sysctl\n");
>  
> @@ -200,18 +202,32 @@ 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_skip(err_pwrite_msg);

It seems like we should have a better way to keep the count balanced than
to require a ksft_test_result_skip() call for each test on each error
path. Every time we add a test we'll have to go add skips everywhere else.

> +		goto err_pwrite;
> +	}
> +
>  	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
>  			 "sysctl disabled\n");
>  
>  	value = '0';
> -	pwrite(fd, &value, 1, 0);
> +	ret = pwrite(fd, &value, 1, 0);
> +	if (ret != 1)
> +		goto err_pwrite;
> +
>  	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0,
>  			 "sysctl enabled\n");
>  
>  	set_tagged_addr_ctrl(0, false);
>  
>  	close(fd);
> +
> +	return;
> +
> +err_pwrite:
> +	close(fd);
> +	ksft_test_result_fail(err_pwrite_msg);
>  }

I don't think the goto reduces much code or improves readability much. A
wrapper function should do better. I was thinking something like

 static bool pwrite_wrapper(int fd, void *buf, size_t count, const char *msg)
 {
   int ret = pwrite(fd, buf, count, 0);
   if (ret != count) {
      ksft_perror(msg);
      return false;
   }
   return true;
 }


 value = '1';
 if (!pwrite_wrapper(fd, &value, 1, "write '1'"))
    ksft_test_result_fail(...);

 value = '0';
 if (!pwrite_wrapper(fd, &value, 1, "write '0'"))
    ksft_test_result_fail(...);


>  
>  static void test_tagged_addr_abi_pmlen(int pmlen)
> 
> ---
> base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> change-id: 20241204-fix_warnings_pointer_masking_tests-3860e4f35429
> -- 
> - Charlie
> 

Thanks,
drew

On Fri, Dec 06, 2024 at 10:15:17AM +0100, Andrew Jones wrote:
> On Thu, Dec 05, 2024 at 01:49:31PM -0800, Charlie Jenkins wrote:
> > 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>
> > ---
> > Changes in v4:
> > - Skip sysctl_enabled test if first pwrite failed
> > - Link to v3: https://lore.kernel.org/r/20241205-fix_warnings_pointer_masking_tests-v3-1-5c28b0f9640d@rivosinc.com
> > 
> > Changes in v3:
> > - Fix sysctl enabled test case (Drew/Alex)
> > - Move pwrite err condition into goto (Drew)
> > - Link to v2: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v2-1-1bf0c5095f58@rivosinc.com
> > 
> > Changes in v2:
> > - I had ret != 2 for testing, I changed it to be ret != 1.
> > - Link to v1: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v1-1-ea1e9665ce7a@rivosinc.com
> > ---
> >  tools/testing/selftests/riscv/abi/pointer_masking.c | 20 ++++++++++++++++++--
> >  1 file changed, 18 insertions(+), 2 deletions(-)
> > 
> > diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c
> > index dee41b7ee3e3..759445d5f265 100644
> > --- a/tools/testing/selftests/riscv/abi/pointer_masking.c
> > +++ b/tools/testing/selftests/riscv/abi/pointer_masking.c
> > @@ -189,6 +189,8 @@ static void test_tagged_addr_abi_sysctl(void)
> >  {
> >  	char value;
> >  	int fd;
> > +	int ret;
> > +	char *err_pwrite_msg = "failed to write to /proc/sys/abi/tagged_addr_disabled\n";
> >  
> >  	ksft_print_msg("Testing tagged address ABI sysctl\n");
> >  
> > @@ -200,18 +202,32 @@ 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_skip(err_pwrite_msg);
> 
> It seems like we should have a better way to keep the count balanced than
> to require a ksft_test_result_skip() call for each test on each error
> path. Every time we add a test we'll have to go add skips everywhere else.

It's only a problem if there are multiple tests in a single test
function like there is here. Since the tests disable then reenable it
makes sense to have them in one function, but does require us to do the
skipping.

> 
> > +		goto err_pwrite;
> > +	}
> > +
> >  	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
> >  			 "sysctl disabled\n");
> >  
> >  	value = '0';
> > -	pwrite(fd, &value, 1, 0);
> > +	ret = pwrite(fd, &value, 1, 0);
> > +	if (ret != 1)
> > +		goto err_pwrite;
> > +
> >  	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0,
> >  			 "sysctl enabled\n");
> >  
> >  	set_tagged_addr_ctrl(0, false);
> >  
> >  	close(fd);
> > +
> > +	return;
> > +
> > +err_pwrite:
> > +	close(fd);
> > +	ksft_test_result_fail(err_pwrite_msg);
> >  }
> 
> I don't think the goto reduces much code or improves readability much. A
> wrapper function should do better. I was thinking something like
> 
>  static bool pwrite_wrapper(int fd, void *buf, size_t count, const char *msg)
>  {
>    int ret = pwrite(fd, buf, count, 0);
>    if (ret != count) {
>       ksft_perror(msg);
>       return false;
>    }
>    return true;
>  }
> 
> 
>  value = '1';
>  if (!pwrite_wrapper(fd, &value, 1, "write '1'"))
>     ksft_test_result_fail(...);
> 
>  value = '0';
>  if (!pwrite_wrapper(fd, &value, 1, "write '0'"))
>     ksft_test_result_fail(...);
> 
> 

Will do, thanks!

- Charlie

> >  
> >  static void test_tagged_addr_abi_pmlen(int pmlen)
> > 
> > ---
> > base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> > change-id: 20241204-fix_warnings_pointer_masking_tests-3860e4f35429
> > -- 
> > - Charlie
> > 
> 
> Thanks,
> drew

On Fri, Dec 06, 2024 at 09:21:50AM -0800, Charlie Jenkins wrote:
> On Fri, Dec 06, 2024 at 10:15:17AM +0100, Andrew Jones wrote:
> > On Thu, Dec 05, 2024 at 01:49:31PM -0800, Charlie Jenkins wrote:
> > > 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>
> > > ---
> > > Changes in v4:
> > > - Skip sysctl_enabled test if first pwrite failed
> > > - Link to v3: https://lore.kernel.org/r/20241205-fix_warnings_pointer_masking_tests-v3-1-5c28b0f9640d@rivosinc.com
> > > 
> > > Changes in v3:
> > > - Fix sysctl enabled test case (Drew/Alex)
> > > - Move pwrite err condition into goto (Drew)
> > > - Link to v2: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v2-1-1bf0c5095f58@rivosinc.com
> > > 
> > > Changes in v2:
> > > - I had ret != 2 for testing, I changed it to be ret != 1.
> > > - Link to v1: https://lore.kernel.org/r/20241204-fix_warnings_pointer_masking_tests-v1-1-ea1e9665ce7a@rivosinc.com
> > > ---
> > >  tools/testing/selftests/riscv/abi/pointer_masking.c | 20 ++++++++++++++++++--
> > >  1 file changed, 18 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/tools/testing/selftests/riscv/abi/pointer_masking.c b/tools/testing/selftests/riscv/abi/pointer_masking.c
> > > index dee41b7ee3e3..759445d5f265 100644
> > > --- a/tools/testing/selftests/riscv/abi/pointer_masking.c
> > > +++ b/tools/testing/selftests/riscv/abi/pointer_masking.c
> > > @@ -189,6 +189,8 @@ static void test_tagged_addr_abi_sysctl(void)
> > >  {
> > >  	char value;
> > >  	int fd;
> > > +	int ret;
> > > +	char *err_pwrite_msg = "failed to write to /proc/sys/abi/tagged_addr_disabled\n";
> > >  
> > >  	ksft_print_msg("Testing tagged address ABI sysctl\n");
> > >  
> > > @@ -200,18 +202,32 @@ 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_skip(err_pwrite_msg);
> > 
> > It seems like we should have a better way to keep the count balanced than
> > to require a ksft_test_result_skip() call for each test on each error
> > path. Every time we add a test we'll have to go add skips everywhere else.
> 
> It's only a problem if there are multiple tests in a single test
> function like there is here. Since the tests disable then reenable it
> makes sense to have them in one function, but does require us to do the
> skipping.

I guess it is sufficient to leave out the skip here, if the first one
fails we can just continue and let the second one fail too.

- Charlie

> 
> > 
> > > +		goto err_pwrite;
> > > +	}
> > > +
> > >  	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == -EINVAL,
> > >  			 "sysctl disabled\n");
> > >  
> > >  	value = '0';
> > > -	pwrite(fd, &value, 1, 0);
> > > +	ret = pwrite(fd, &value, 1, 0);
> > > +	if (ret != 1)
> > > +		goto err_pwrite;
> > > +
> > >  	ksft_test_result(set_tagged_addr_ctrl(min_pmlen, true) == 0,
> > >  			 "sysctl enabled\n");
> > >  
> > >  	set_tagged_addr_ctrl(0, false);
> > >  
> > >  	close(fd);
> > > +
> > > +	return;
> > > +
> > > +err_pwrite:
> > > +	close(fd);
> > > +	ksft_test_result_fail(err_pwrite_msg);
> > >  }
> > 
> > I don't think the goto reduces much code or improves readability much. A
> > wrapper function should do better. I was thinking something like
> > 
> >  static bool pwrite_wrapper(int fd, void *buf, size_t count, const char *msg)
> >  {
> >    int ret = pwrite(fd, buf, count, 0);
> >    if (ret != count) {
> >       ksft_perror(msg);
> >       return false;
> >    }
> >    return true;
> >  }
> > 
> > 
> >  value = '1';
> >  if (!pwrite_wrapper(fd, &value, 1, "write '1'"))
> >     ksft_test_result_fail(...);
> > 
> >  value = '0';
> >  if (!pwrite_wrapper(fd, &value, 1, "write '0'"))
> >     ksft_test_result_fail(...);
> > 
> > 
> 
> Will do, thanks!
> 
> - Charlie
> 
> > >  
> > >  static void test_tagged_addr_abi_pmlen(int pmlen)
> > > 
> > > ---
> > > base-commit: 40384c840ea1944d7c5a392e8975ed088ecf0b37
> > > change-id: 20241204-fix_warnings_pointer_masking_tests-3860e4f35429
> > > -- 
> > > - Charlie
> > > 
> > 
> > Thanks,
> > drew