Re: [PATCH bpf] bpf: selftest: Fix flaky tcp_hdr_options test when adding addr to lo

On Tue, Oct 13, 2020 at 4:13 AM Martin KaFai Lau [off-list ref] wrote:

The tcp_hdr_options test adds a "::eB9F" addr to the lo dev.
However, this non loopback address will have a race on ipv6 dad
which may lead to EADDRNOTAVAIL error from time to time.

Even nodad is used in the iproute2 command, there is still a race in
when the route will be added.  This will then lead to ENETUNREACH from
time to time.

To avoid the above, this patch uses the default loopback address "::1"
to do the test.

Fixes: ad2f8eb0095e ("bpf: selftests: Tcp header options")
Reported-by: Andrii Nakryiko <redacted>
Signed-off-by: Martin KaFai Lau <redacted>
---

Less shelling out is always good :)

Acked-by: Andrii Nakryiko <andrii@kernel.org>

 .../bpf/prog_tests/tcp_hdr_options.c          | 26 +------------------
 .../bpf/progs/test_misc_tcp_hdr_options.c     |  2 +-
 2 files changed, 2 insertions(+), 26 deletions(-)

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