splice_short grows its pipe with (MAX_FRAGS + 1) * 0x1000 so it can queue one short vmsplice() buffer for each fragment before draining the pipe. That assumes 4K pipe buffers. On 64K-page kernels the request is rounded to 262144 bytes, which provides only four pipe buffers. The fifth one-byte vmsplice() blocks in pipe_wait_writable and the test times out before it reaches the TLS path. Request enough bytes for the same number of pipe buffers using the runtime page size, and assert that the kernel granted at least that much. If an unprivileged run cannot raise the pipe above the system pipe-max-size limit, skip the test because it cannot exercise the intended path. Fixes: 3667e9b442b9 ("selftests: tls: add test for short splice due to full skmsg") Assisted-by: Codex:gpt-5 Signed-off-by: Nirmoy Das Reviewed-by: Simon Horman --- v2: Remove redundant ASSERT_GE(ret, 0) (Simon Horman). tools/testing/selftests/net/tls.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/net/tls.c b/tools/testing/selftests/net/tls.c index 30a236b8e9f73..d805a7dfbdd51 100644 --- a/tools/testing/selftests/net/tls.c +++ b/tools/testing/selftests/net/tls.c @@ -997,6 +997,8 @@ TEST_F(tls, splice_short) char sendbuf[0x100]; char sendchar = 'S'; int pipefds[2]; + int pipe_sz; + int ret; int i; sendchar_iov.iov_base = &sendchar; @@ -1005,7 +1007,11 @@ TEST_F(tls, splice_short) memset(sendbuf, 's', sizeof(sendbuf)); ASSERT_GE(pipe2(pipefds, O_NONBLOCK), 0); - ASSERT_GE(fcntl(pipefds[0], F_SETPIPE_SZ, (MAX_FRAGS + 1) * 0x1000), 0); + pipe_sz = (MAX_FRAGS + 1) * getpagesize(); + ret = fcntl(pipefds[0], F_SETPIPE_SZ, pipe_sz); + if (ret < 0 && errno == EPERM) + SKIP(return, "insufficient pipe capacity"); + ASSERT_GE(ret, pipe_sz); for (i = 0; i < MAX_FRAGS; i++) ASSERT_GE(vmsplice(pipefds[1], &sendchar_iov, 1, 0), 0); base-commit: 47186409c092cd7dd70350999186c700233e854d -- 2.43.0