From: Oleg Nesterov Date: Wed, 29 Jul 2026 11:33:45 +0000 (+0200) Subject: selftests/epoll: add a regression test for pipe->poll_usage X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=ab018b7733bd8f5f998d476528c24924ebeb9959;p=thirdparty%2Flinux.git selftests/epoll: add a regression test for pipe->poll_usage pipe->poll_usage was added to ensure that edge-triggered epoll consumers get a wakeup on every write, even if the pipe was already non-empty. However, none of the existing epoll_wakeup_test cases cover this; the test suite passes even with WRITE_ONCE(pipe->poll_usage, true) removed. Add a test that writes twice to a pipe and verifies that epoll_wait with EPOLLET reports data each time. This covers the pipe-specific per-write wakeup behavior that edge-triggered consumers depend on. Signed-off-by: Oleg Nesterov Link: https://patch.msgid.link/amnlGZesXu-SUK2H@redhat.com Signed-off-by: Christian Brauner (Amutable) --- diff --git a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c index f6f1a7ff01b05..81a994943e121 100644 --- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c +++ b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c @@ -3538,4 +3538,27 @@ TEST(epoll65) close(ctx.efd[1]); } +TEST(epoll66) +{ + struct epoll_event event; + int pfd[2], efd; + + ASSERT_EQ(pipe(pfd), 0); + + efd = epoll_create1(0); + ASSERT_GE(efd, 0); + + event.events = EPOLLIN | EPOLLET; + ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, pfd[0], &event), 0); + + for (int i = 0; i < 2; ++i) { + ASSERT_EQ(write(pfd[1], "", 1), 1); + EXPECT_EQ(epoll_wait(efd, &event, 1, 0), 1); + } + + close(pfd[0]); + close(pfd[1]); + close(efd); +} + TEST_HARNESS_MAIN