[PATCH bpf] selftests/bpf: Fix broken build where char is unsigned

[PATCH bpf] selftests/bpf: Fix broken build where char is unsigned

[Björn Töpel]

From: Björn Töpel <bjorn@rivosinc.com>

There are architectures where char is not signed. If so, the following
error is triggered:

  | xdp_hw_metadata.c:435:42: error: result of comparison of constant -1 \
  |   with expression of type 'char' is always true \
  |   [-Werror,-Wtautological-constant-out-of-range-compare]
  |   435 |         while ((opt = getopt(argc, argv, "mh")) != -1) {
  |       |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~
  | 1 error generated.

Correct by changing the char to int.

Fixes: bb6a88885fde ("selftests/bpf: Add options and frags to xdp_hw_metadata")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
---
 tools/testing/selftests/bpf/xdp_hw_metadata.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
index 17c0f92ff160..c3ba40d0b9de 100644
--- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
+++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
@@ -430,7 +430,7 @@ static void print_usage(void)
 
 static void read_args(int argc, char *argv[])
 {
-	char opt;
+	int opt;
 
 	while ((opt = getopt(argc, argv, "mh")) != -1) {
 		switch (opt) {

base-commit: cb3c6a58be50c65014296aa3455cae0fa1e82eac
-- 
2.40.1

Re: [PATCH bpf] selftests/bpf: Fix broken build where char is unsigned

[Larysa Zaremba]

On Thu, Nov 02, 2023 at 11:35:37AM +0100, Björn Töpel wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
> 
> There are architectures where char is not signed. If so, the following
> error is triggered:
> 
>   | xdp_hw_metadata.c:435:42: error: result of comparison of constant -1 \
>   |   with expression of type 'char' is always true \
>   |   [-Werror,-Wtautological-constant-out-of-range-compare]
>   |   435 |         while ((opt = getopt(argc, argv, "mh")) != -1) {
>   |       |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~
>   | 1 error generated.
> 
> Correct by changing the char to int.
> 
> Fixes: bb6a88885fde ("selftests/bpf: Add options and frags to xdp_hw_metadata")
> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

Acked-by: Larysa Zaremba <larysa.zaremba@intel.com>

> ---
>  tools/testing/selftests/bpf/xdp_hw_metadata.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> index 17c0f92ff160..c3ba40d0b9de 100644
> --- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
> +++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> @@ -430,7 +430,7 @@ static void print_usage(void)
>  
>  static void read_args(int argc, char *argv[])
>  {
> -	char opt;
> +	int opt;
>  
>  	while ((opt = getopt(argc, argv, "mh")) != -1) {
>  		switch (opt) {
> 
> base-commit: cb3c6a58be50c65014296aa3455cae0fa1e82eac
> -- 
> 2.40.1
> 
> 

Re: [PATCH bpf] selftests/bpf: Fix broken build where char is unsigned

[Anders Roxell]

On 2023-11-02 11:35, Björn Töpel wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
> 
> There are architectures where char is not signed. If so, the following
> error is triggered:
> 
>   | xdp_hw_metadata.c:435:42: error: result of comparison of constant -1 \
>   |   with expression of type 'char' is always true \
>   |   [-Werror,-Wtautological-constant-out-of-range-compare]
>   |   435 |         while ((opt = getopt(argc, argv, "mh")) != -1) {
>   |       |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~
>   | 1 error generated.
> 
> Correct by changing the char to int.
> 
> Fixes: bb6a88885fde ("selftests/bpf: Add options and frags to xdp_hw_metadata")
> Signed-off-by: Björn Töpel <bjorn@rivosinc.com>

Thank you for the patch.
I saw the same failure when I built selftests/bpf for arm64.

With this patch ontop of today's next-20231102, fixes that build issue.

Tested-by: Anders Roxell <anders.roxell@linaro.org>


Cheers,
Anders

> ---
>  tools/testing/selftests/bpf/xdp_hw_metadata.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/bpf/xdp_hw_metadata.c b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> index 17c0f92ff160..c3ba40d0b9de 100644
> --- a/tools/testing/selftests/bpf/xdp_hw_metadata.c
> +++ b/tools/testing/selftests/bpf/xdp_hw_metadata.c
> @@ -430,7 +430,7 @@ static void print_usage(void)
>  
>  static void read_args(int argc, char *argv[])
>  {
> -	char opt;
> +	int opt;
>  
>  	while ((opt = getopt(argc, argv, "mh")) != -1) {
>  		switch (opt) {
> 
> base-commit: cb3c6a58be50c65014296aa3455cae0fa1e82eac
> -- 
> 2.40.1
> 

Re: [PATCH bpf] selftests/bpf: Fix broken build where char is unsigned

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Thu,  2 Nov 2023 11:35:37 +0100 you wrote:
> From: Björn Töpel <bjorn@rivosinc.com>
> 
> There are architectures where char is not signed. If so, the following
> error is triggered:
> 
>   | xdp_hw_metadata.c:435:42: error: result of comparison of constant -1 \
>   |   with expression of type 'char' is always true \
>   |   [-Werror,-Wtautological-constant-out-of-range-compare]
>   |   435 |         while ((opt = getopt(argc, argv, "mh")) != -1) {
>   |       |                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^  ~~
>   | 1 error generated.
> 
> [...]

Here is the summary with links:
  - [bpf] selftests/bpf: Fix broken build where char is unsigned
    https://git.kernel.org/bpf/bpf/c/d84b139f53e8

You are awesome, thank you!
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