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From: Hou Tao <houtao1@huawei.com>
To: Martin KaFai Lau <kafai@fb.com>
Cc: <netdev@vger.kernel.org>, <bpf@vger.kernel.org>
Subject: Question about the release of BPF_MAP_TYPE_STRUCT_OPS fd
Date: Tue, 28 Sep 2021 22:13:45 +0800	[thread overview]
Message-ID: <a6ba3289-accd-051a-b27c-d90df0eb7cd2@huawei.com> (raw)

Hi Martin,

During the testing of bpf_tcp_ca, I found that if the test program
aborts before calling bpf_link__detach_struct_ops(), the registered
bpf_dctcp will not be unregistered, and running bpf_tcp_ca test again
will fail with -EEXIST error as shown below:

test_dctcp:PASS:bpf_dctcp__open_and_load 0 nsec
test_dctcp:FAIL:bpf_map__attach_struct_ops unexpected error: -17

The root cause is that the release of BPF_MAP_TYPE_STRUCT_OPS fd
neither put struct_ops programs in maps nor unregister the struct_ops
from kernel. Was the implementation intentional, or was it an oversight ?
If it is an oversight, I will post a patch to fix it.

Regards,
Tao

             reply	other threads:[~2021-09-28 14:13 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-28 14:13 Hou Tao [this message]
2021-09-28 18:33 ` Question about the release of BPF_MAP_TYPE_STRUCT_OPS fd Martin KaFai Lau

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