[PATCH] libbpf: Initialize err in probe_map_create

[PATCH] libbpf: Initialize err in probe_map_create

[Florian Fainelli]

GCC-11 warns about the possibly unitialized err variable in
probe_map_create:

libbpf_probes.c: In function 'probe_map_create':
libbpf_probes.c:361:38: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  361 |                 return fd < 0 && err == exp_err ? 1 : 0;
      |                                  ~~~~^~~~~~~~~~

Fixes: 878d8def0603 ("libbpf: Rework feature-probing APIs")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
---
 tools/lib/bpf/libbpf_probes.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 97b06cede56f..6cf44e61815d 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -247,7 +247,7 @@ static int probe_map_create(enum bpf_map_type map_type, __u32 ifindex)
 	LIBBPF_OPTS(bpf_map_create_opts, opts);
 	int key_size, value_size, max_entries;
 	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
-	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err;
+	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;
 
 	opts.map_ifindex = ifindex;
 
-- 
2.25.1

Re: [PATCH] libbpf: Initialize err in probe_map_create

[Jiri Olsa]

On Sun, Jul 31, 2022 at 07:51:09PM -0700, Florian Fainelli wrote:
> GCC-11 warns about the possibly unitialized err variable in
> probe_map_create:
> 
> libbpf_probes.c: In function 'probe_map_create':
> libbpf_probes.c:361:38: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   361 |                 return fd < 0 && err == exp_err ? 1 : 0;
>       |                                  ~~~~^~~~~~~~~~
> 
> Fixes: 878d8def0603 ("libbpf: Rework feature-probing APIs")
> Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
>  tools/lib/bpf/libbpf_probes.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
> index 97b06cede56f..6cf44e61815d 100644
> --- a/tools/lib/bpf/libbpf_probes.c
> +++ b/tools/lib/bpf/libbpf_probes.c
> @@ -247,7 +247,7 @@ static int probe_map_create(enum bpf_map_type map_type, __u32 ifindex)
>  	LIBBPF_OPTS(bpf_map_create_opts, opts);
>  	int key_size, value_size, max_entries;
>  	__u32 btf_key_type_id = 0, btf_value_type_id = 0;
> -	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err;
> +	int fd = -1, btf_fd = -1, fd_inner = -1, exp_err = 0, err = 0;
>  
>  	opts.map_ifindex = ifindex;
>  
> -- 
> 2.25.1
> 

Re: [PATCH] libbpf: Initialize err in probe_map_create

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Andrii Nakryiko <andrii@kernel.org>:

On Sun, 31 Jul 2022 19:51:09 -0700 you wrote:
> GCC-11 warns about the possibly unitialized err variable in
> probe_map_create:
> 
> libbpf_probes.c: In function 'probe_map_create':
> libbpf_probes.c:361:38: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   361 |                 return fd < 0 && err == exp_err ? 1 : 0;
>       |                                  ~~~~^~~~~~~~~~
> 
> [...]

Here is the summary with links:
  - libbpf: Initialize err in probe_map_create
    https://git.kernel.org/bpf/bpf-next/c/3045f42a6432

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

Re: [PATCH] libbpf: Initialize err in probe_map_create

[Florian Fainelli]

On 8/4/2022 2:50 PM, patchwork-bot+netdevbpf@kernel.org wrote:
> Hello:
> 
> This patch was applied to bpf/bpf-next.git (master)
> by Andrii Nakryiko <andrii@kernel.org>:
> 
> On Sun, 31 Jul 2022 19:51:09 -0700 you wrote:
>> GCC-11 warns about the possibly unitialized err variable in
>> probe_map_create:
>>
>> libbpf_probes.c: In function 'probe_map_create':
>> libbpf_probes.c:361:38: error: 'err' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>>    361 |                 return fd < 0 && err == exp_err ? 1 : 0;
>>        |                                  ~~~~^~~~~~~~~~
>>
>> [...]
> 
> Here is the summary with links:
>    - libbpf: Initialize err in probe_map_create
>      https://git.kernel.org/bpf/bpf-next/c/3045f42a6432
> 
> You are awesome, thank you!

Thanks for applying, I was sort of expecting this patch to land to Linus 
a bit quicker, as far as I can see it is still only in linux-next yet it 
does fix a build warning turned error. Any chance of fast tracking it?

Thanks!
-- 
Florian