Re: [PATCH net-next] selftests: tls: avoid flakiness in data_steal

[Sabrina Dubroca <sd@queasysnail.net>]

2026-01-06, 12:02:05 -0800, Jakub Kicinski wrote:
> We see the following failure a few times a week:
> 
>   #  RUN           global.data_steal ...
>   # tls.c:3280:data_steal:Expected recv(cfd, buf2, sizeof(buf2), MSG_DONTWAIT) (10000) == -1 (-1)
>   # data_steal: Test failed
>   #          FAIL  global.data_steal
>   not ok 8 global.data_steal
> 
> The 10000 bytes read suggests that the child process did a recv()
> of half of the data using the TLS ULP and we're now getting the
> remaining half. The intent of the test is to get the child to
> enter _TCP_ recvmsg handler, so it needs to enter the syscall before
> parent installed the TLS recvmsg with setsockopt(SOL_TLS).
> 
> Instead of the 10msec sleep send 1 byte of data and wait for the
> child to consume it.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> CC: sd@queasysnail.net
> CC: shuah@kernel.org
> CC: linux-kselftest@vger.kernel.org
> ---
>  tools/testing/selftests/net/tls.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)

Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>

-- 
Sabrina