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authorDavidlohr Bueso <dave@stgolabs.net>2021-05-07 04:04:04 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-07 05:24:13 +0300
commit1e3b918d1dd18bcea3df9339c2d8910ffa95686a (patch)
tree6f3c8b7b168746727fa972d604bbfe22e640b0d1 /tools
parent7e6cdd7fd94380a3b87b2ce087903b3722b3d0d6 (diff)
downloadlinux-1e3b918d1dd18bcea3df9339c2d8910ffa95686a.tar.xz
kselftest: introduce new epoll test case
Patch series "fs/epoll: restore user-visible behavior upon event ready". This series tries to address a change in user visible behavior, reported in https://bugzilla.kernel.org/show_bug.cgi?id=208943. Epoll does not report an event to all the threads running epoll_wait() on the same epoll descriptor. Unsurprisingly, this was bisected back to 339ddb53d373 (fs/epoll: remove unnecessary wakeups of nested epoll), which has had various problems in the past, beyond only nested epoll usage. This patch (of 2): This incorporates the testcase originally reported in: https://bugzilla.kernel.org/show_bug.cgi?id=208943 Which ensures an event is reported to all threads blocked on the same epoll descriptor, otherwise only a single thread will receive the wakeup once the event become ready. Link: https://lkml.kernel.org/r/20210405231025.33829-1-dave@stgolabs.net Link: https://lkml.kernel.org/r/20210405231025.33829-2-dave@stgolabs.net Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Cc: Jason Baron <jbaron@akamai.com> Cc: Roman Penyaev <rpenyaev@suse.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c44
1 files changed, 44 insertions, 0 deletions
diff --git a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
index ad7fabd575f9..65ede506305c 100644
--- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
+++ b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
@@ -3449,4 +3449,48 @@ TEST(epoll63)
close(sfd[1]);
}
+/*
+ * t0 t1
+ * (ew) \ / (ew)
+ * e0
+ * | (lt)
+ * s0
+ */
+TEST(epoll64)
+{
+ pthread_t waiter[2];
+ struct epoll_event e;
+ struct epoll_mtcontext ctx = { 0 };
+
+ signal(SIGUSR1, signal_handler);
+
+ ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, ctx.sfd), 0);
+
+ ctx.efd[0] = epoll_create(1);
+ ASSERT_GE(ctx.efd[0], 0);
+
+ e.events = EPOLLIN;
+ ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);
+
+ /*
+ * main will act as the emitter once both waiter threads are
+ * blocked and expects to both be awoken upon the ready event.
+ */
+ ctx.main = pthread_self();
+ ASSERT_EQ(pthread_create(&waiter[0], NULL, waiter_entry1a, &ctx), 0);
+ ASSERT_EQ(pthread_create(&waiter[1], NULL, waiter_entry1a, &ctx), 0);
+
+ usleep(100000);
+ ASSERT_EQ(write(ctx.sfd[1], "w", 1), 1);
+
+ ASSERT_EQ(pthread_join(waiter[0], NULL), 0);
+ ASSERT_EQ(pthread_join(waiter[1], NULL), 0);
+
+ EXPECT_EQ(ctx.count, 2);
+
+ close(ctx.efd[0]);
+ close(ctx.sfd[0]);
+ close(ctx.sfd[1]);
+}
+
TEST_HARNESS_MAIN