* [PATCH bpf-next] libbpf: Skip the pinning of global data map for old kernels.
@ 2021-12-09 8:44 Shuyi Cheng
2021-12-09 17:26 ` Andrii Nakryiko
0 siblings, 1 reply; 3+ messages in thread
From: Shuyi Cheng @ 2021-12-09 8:44 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, open list:BPF (Safe dynamic programs and tools),
open list:BPF (Safe dynamic programs and tools)
Fix error: "failed to pin map: Bad file descriptor, path:
/sys/fs/bpf/_rodata_str1_1."
In the old kernel, the global data map will not be created, see [0]. So
we should skip the pinning of the global data map to avoid
bpf_object__pin_maps returning error.
[0]: https://lore.kernel.org/bpf/20211123200105.387855-1-andrii@kernel.org
Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
---
tools/lib/bpf/libbpf.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6db0b5e8540e..d96cf49cebab 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -7884,6 +7884,10 @@ int bpf_object__pin_maps(struct bpf_object *obj,
const char *path)
char *pin_path = NULL;
char buf[PATH_MAX];
+ if (bpf_map__is_internal(map) &&
+ !kernel_supports(obj, FEAT_GLOBAL_DATA))
+ continue;
+
if (path) {
int len;
--
2.19.1.6.gb485710b
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] libbpf: Skip the pinning of global data map for old kernels.
2021-12-09 8:44 [PATCH bpf-next] libbpf: Skip the pinning of global data map for old kernels Shuyi Cheng
@ 2021-12-09 17:26 ` Andrii Nakryiko
2021-12-10 3:02 ` Shuyi Cheng
0 siblings, 1 reply; 3+ messages in thread
From: Andrii Nakryiko @ 2021-12-09 17:26 UTC (permalink / raw)
To: Shuyi Cheng
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, open list:BPF (Safe dynamic programs and tools),
open list:BPF (Safe dynamic programs and tools)
On Thu, Dec 9, 2021 at 12:44 AM Shuyi Cheng
<chengshuyi@linux.alibaba.com> wrote:
>
>
> Fix error: "failed to pin map: Bad file descriptor, path:
> /sys/fs/bpf/_rodata_str1_1."
>
> In the old kernel, the global data map will not be created, see [0]. So
> we should skip the pinning of the global data map to avoid
> bpf_object__pin_maps returning error.
>
> [0]: https://lore.kernel.org/bpf/20211123200105.387855-1-andrii@kernel.org
>
> Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
> ---
> tools/lib/bpf/libbpf.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 6db0b5e8540e..d96cf49cebab 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -7884,6 +7884,10 @@ int bpf_object__pin_maps(struct bpf_object *obj,
> const char *path)
> char *pin_path = NULL;
> char buf[PATH_MAX];
>
> + if (bpf_map__is_internal(map) &&
> + !kernel_supports(obj, FEAT_GLOBAL_DATA))
doing the same check in 3 different places sucks. Let's add "bool
skipped" to struct bpf_map, which will be set in one place (at the map
creation time) and then check during relocation and during pinning?
> + continue;
> +
> if (path) {
> int len;
>
> --
> 2.19.1.6.gb485710b
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next] libbpf: Skip the pinning of global data map for old kernels.
2021-12-09 17:26 ` Andrii Nakryiko
@ 2021-12-10 3:02 ` Shuyi Cheng
0 siblings, 0 replies; 3+ messages in thread
From: Shuyi Cheng @ 2021-12-10 3:02 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko,
Martin KaFai Lau, Song Liu, Yonghong Song, John Fastabend,
KP Singh, open list:BPF (Safe dynamic programs and tools),
open list:BPF (Safe dynamic programs and tools)
On 12/10/21 1:26 AM, Andrii Nakryiko wrote:
> On Thu, Dec 9, 2021 at 12:44 AM Shuyi Cheng
> <chengshuyi@linux.alibaba.com> wrote:
>>
>>
>> Fix error: "failed to pin map: Bad file descriptor, path:
>> /sys/fs/bpf/_rodata_str1_1."
>>
>> In the old kernel, the global data map will not be created, see [0]. So
>> we should skip the pinning of the global data map to avoid
>> bpf_object__pin_maps returning error.
>>
>> [0]: https://lore.kernel.org/bpf/20211123200105.387855-1-andrii@kernel.org
>>
>> Signed-off-by: Shuyi Cheng <chengshuyi@linux.alibaba.com>
>> ---
>> tools/lib/bpf/libbpf.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
>> index 6db0b5e8540e..d96cf49cebab 100644
>> --- a/tools/lib/bpf/libbpf.c
>> +++ b/tools/lib/bpf/libbpf.c
>> @@ -7884,6 +7884,10 @@ int bpf_object__pin_maps(struct bpf_object *obj,
>> const char *path)
>> char *pin_path = NULL;
>> char buf[PATH_MAX];
>>
>> + if (bpf_map__is_internal(map) &&
>> + !kernel_supports(obj, FEAT_GLOBAL_DATA))
>
>
> doing the same check in 3 different places sucks. Let's add "bool
> skipped" to struct bpf_map, which will be set in one place (at the map
> creation time) and then check during relocation and during pinning?
>
Agree, thanks.
regards,
Shuyi
>> + continue;
>> +
>> if (path) {
>> int len;
>>
>> --
>> 2.19.1.6.gb485710b
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-12-09 8:44 [PATCH bpf-next] libbpf: Skip the pinning of global data map for old kernels Shuyi Cheng
2021-12-09 17:26 ` Andrii Nakryiko
2021-12-10 3:02 ` Shuyi Cheng
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