[PATCH] tools/bpftool: Fix error return code in do_skeleton()

[PATCH] tools/bpftool: Fix error return code in do_skeleton()

[YueHaibing]

The error return code should be PTR_ERR(obj) other than
PTR_ERR(NULL).

Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
---
 tools/bpf/bpftool/gen.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index 10de76b296ba..35f62273cdbd 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -305,8 +305,9 @@ static int do_skeleton(int argc, char **argv)
 	opts.object_name = obj_name;
 	obj = bpf_object__open_mem(obj_data, file_sz, &opts);
 	if (IS_ERR(obj)) {
+		err = PTR_ERR(obj);
+		p_err("failed to open BPF object file: %ld", err);
 		obj = NULL;
-		p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
 		goto out;
 	}
 
-- 
2.17.1

Re: [PATCH] tools/bpftool: Fix error return code in do_skeleton()

[Quentin Monnet]

2020-07-15 11:13 UTC+0800 ~ YueHaibing <yuehaibing@huawei.com>
> The error return code should be PTR_ERR(obj) other than
> PTR_ERR(NULL).
> 
> Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>


Reviewed-by: Quentin Monnet <quentin@isovalent.com>

Thanks!

Re: [PATCH] tools/bpftool: Fix error return code in do_skeleton()

[Daniel Borkmann]

On 7/15/20 5:13 AM, YueHaibing wrote:
> The error return code should be PTR_ERR(obj) other than
> PTR_ERR(NULL).
> 
> Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> ---
>   tools/bpf/bpftool/gen.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
> index 10de76b296ba..35f62273cdbd 100644
> --- a/tools/bpf/bpftool/gen.c
> +++ b/tools/bpf/bpftool/gen.c
> @@ -305,8 +305,9 @@ static int do_skeleton(int argc, char **argv)
>   	opts.object_name = obj_name;
>   	obj = bpf_object__open_mem(obj_data, file_sz, &opts);
>   	if (IS_ERR(obj)) {
> +		err = PTR_ERR(obj);
> +		p_err("failed to open BPF object file: %ld", err);
>   		obj = NULL;
> -		p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
>   		goto out;

Instead of just the error number, could we dump something useful to the user here
via libbpf_strerror() given you touch this line? Also, I think the convention in
do_skeleton() is to just return {0,-1} given this is propagated as return code
for bpftool.

>   	}
>   
> 

[PATCH v2] tools/bpftool: Fix error handing in do_skeleton()

[YueHaibing]

Fix pass 0 to PTR_ERR, also dump more err info using
libbpf_strerror.

Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
---
v2: use libbpf_strerror
---
 tools/bpf/bpftool/gen.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index b59d26e89367..8a4c2b3b0cd6 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -302,8 +302,11 @@ static int do_skeleton(int argc, char **argv)
 	opts.object_name = obj_name;
 	obj = bpf_object__open_mem(obj_data, file_sz, &opts);
 	if (IS_ERR(obj)) {
+		char err_buf[256];
+
+		libbpf_strerror(PTR_ERR(obj), err_buf, sizeof(err_buf));
+		p_err("failed to open BPF object file: %s", err_buf);
 		obj = NULL;
-		p_err("failed to open BPF object file: %ld", PTR_ERR(obj));
 		goto out;
 	}
 
-- 
2.17.1

Re: [PATCH v2] tools/bpftool: Fix error handing in do_skeleton()

[Alexei Starovoitov]

On Fri, Jul 17, 2020 at 5:31 AM YueHaibing <yuehaibing@huawei.com> wrote:
>
> Fix pass 0 to PTR_ERR, also dump more err info using
> libbpf_strerror.
>
> Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
> Signed-off-by: YueHaibing <yuehaibing@huawei.com>
> Reviewed-by: Quentin Monnet <quentin@isovalent.com>

Applied. Thanks