1 files changed, 423 insertions, 1 deletions

diff --git a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
index 37a04dab56f0..65ede506305c 100644
--- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
+++ b/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
@@ -1,24 +1,41 @@
 // SPDX-License-Identifier: GPL-2.0
 
 #define _GNU_SOURCE
+#include <asm/unistd.h>
+#include <linux/time_types.h>
 #include <poll.h>
 #include <unistd.h>
+#include <assert.h>
 #include <signal.h>
 #include <pthread.h>
 #include <sys/epoll.h>
 #include <sys/socket.h>
+#include <sys/eventfd.h>
 #include "../../kselftest_harness.h"
 
 struct epoll_mtcontext
 {
 	int efd[3];
 	int sfd[4];
-	int count;
+	volatile int count;
 
 	pthread_t main;
 	pthread_t waiter;
 };
 
+#ifndef __NR_epoll_pwait2
+#define __NR_epoll_pwait2 -1
+#endif
+
+static inline int sys_epoll_pwait2(int fd, struct epoll_event *events,
+				   int maxevents,
+				   const struct __kernel_timespec *timeout,
+				   const sigset_t *sigset, size_t sigsetsize)
+{
+	return syscall(__NR_epoll_pwait2, fd, events, maxevents, timeout,
+		       sigset, sigsetsize);
+}
+
 static void signal_handler(int signum)
 {
 }
@@ -3071,4 +3088,409 @@ TEST(epoll58)
 	close(ctx.sfd[3]);
 }
 
+static void *epoll59_thread(void *ctx_)
+{
+	struct epoll_mtcontext *ctx = ctx_;
+	struct epoll_event e;
+	int i;
+
+	for (i = 0; i < 100000; i++) {
+		while (ctx->count == 0)
+			;
+
+		e.events = EPOLLIN | EPOLLERR | EPOLLET;
+		epoll_ctl(ctx->efd[0], EPOLL_CTL_MOD, ctx->sfd[0], &e);
+		ctx->count = 0;
+	}
+
+	return NULL;
+}
+
+/*
+ *        t0
+ *      (p) \
+ *           e0
+ *     (et) /
+ *        e0
+ *
+ * Based on https://bugzilla.kernel.org/show_bug.cgi?id=205933
+ */
+TEST(epoll59)
+{
+	pthread_t emitter;
+	struct pollfd pfd;
+	struct epoll_event e;
+	struct epoll_mtcontext ctx = { 0 };
+	int i, ret;
+
+	signal(SIGUSR1, signal_handler);
+
+	ctx.efd[0] = epoll_create1(0);
+	ASSERT_GE(ctx.efd[0], 0);
+
+	ctx.sfd[0] = eventfd(1, 0);
+	ASSERT_GE(ctx.sfd[0], 0);
+
+	e.events = EPOLLIN | EPOLLERR | EPOLLET;
+	ASSERT_EQ(epoll_ctl(ctx.efd[0], EPOLL_CTL_ADD, ctx.sfd[0], &e), 0);
+
+	ASSERT_EQ(pthread_create(&emitter, NULL, epoll59_thread, &ctx), 0);
+
+	for (i = 0; i < 100000; i++) {
+		ret = epoll_wait(ctx.efd[0], &e, 1, 1000);
+		ASSERT_GT(ret, 0);
+
+		while (ctx.count != 0)
+			;
+		ctx.count = 1;
+	}
+	if (pthread_tryjoin_np(emitter, NULL) < 0) {
+		pthread_kill(emitter, SIGUSR1);
+		pthread_join(emitter, NULL);
+	}
+	close(ctx.efd[0]);
+	close(ctx.sfd[0]);
+}
+
+enum {
+	EPOLL60_EVENTS_NR = 10,
+};
+
+struct epoll60_ctx {
+	volatile int stopped;
+	int ready;
+	int waiters;
+	int epfd;
+	int evfd[EPOLL60_EVENTS_NR];
+};
+
+static void *epoll60_wait_thread(void *ctx_)
+{
+	struct epoll60_ctx *ctx = ctx_;
+	struct epoll_event e;
+	sigset_t sigmask;
+	uint64_t v;
+	int ret;
+
+	/* Block SIGUSR1 */
+	sigemptyset(&sigmask);
+	sigaddset(&sigmask, SIGUSR1);
+	sigprocmask(SIG_SETMASK, &sigmask, NULL);
+
+	/* Prepare empty mask for epoll_pwait() */
+	sigemptyset(&sigmask);
+
+	while (!ctx->stopped) {
+		/* Mark we are ready */
+		__atomic_fetch_add(&ctx->ready, 1, __ATOMIC_ACQUIRE);
+
+		/* Start when all are ready */
+		while (__atomic_load_n(&ctx->ready, __ATOMIC_ACQUIRE) &&
+		       !ctx->stopped);
+
+		/* Account this waiter */
+		__atomic_fetch_add(&ctx->waiters, 1, __ATOMIC_ACQUIRE);
+
+		ret = epoll_pwait(ctx->epfd, &e, 1, 2000, &sigmask);
+		if (ret != 1) {
+			/* We expect only signal delivery on stop */
+			assert(ret < 0 && errno == EINTR && "Lost wakeup!\n");
+			assert(ctx->stopped);
+			break;
+		}
+
+		ret = read(e.data.fd, &v, sizeof(v));
+		/* Since we are on ET mode, thus each thread gets its own fd. */
+		assert(ret == sizeof(v));
+
+		__atomic_fetch_sub(&ctx->waiters, 1, __ATOMIC_RELEASE);
+	}
+
+	return NULL;
+}
+
+static inline unsigned long long msecs(void)
+{
+	struct timespec ts;
+	unsigned long long msecs;
+
+	clock_gettime(CLOCK_REALTIME, &ts);
+	msecs = ts.tv_sec * 1000ull;
+	msecs += ts.tv_nsec / 1000000ull;
+
+	return msecs;
+}
+
+static inline int count_waiters(struct epoll60_ctx *ctx)
+{
+	return __atomic_load_n(&ctx->waiters, __ATOMIC_ACQUIRE);
+}
+
+TEST(epoll60)
+{
+	struct epoll60_ctx ctx = { 0 };
+	pthread_t waiters[ARRAY_SIZE(ctx.evfd)];
+	struct epoll_event e;
+	int i, n, ret;
+
+	signal(SIGUSR1, signal_handler);
+
+	ctx.epfd = epoll_create1(0);
+	ASSERT_GE(ctx.epfd, 0);
+
+	/* Create event fds */
+	for (i = 0; i < ARRAY_SIZE(ctx.evfd); i++) {
+		ctx.evfd[i] = eventfd(0, EFD_NONBLOCK);
+		ASSERT_GE(ctx.evfd[i], 0);
+
+		e.events = EPOLLIN | EPOLLET;
+		e.data.fd = ctx.evfd[i];
+		ASSERT_EQ(epoll_ctl(ctx.epfd, EPOLL_CTL_ADD, ctx.evfd[i], &e), 0);
+	}
+
+	/* Create waiter threads */
+	for (i = 0; i < ARRAY_SIZE(waiters); i++)
+		ASSERT_EQ(pthread_create(&waiters[i], NULL,
+					 epoll60_wait_thread, &ctx), 0);
+
+	for (i = 0; i < 300; i++) {
+		uint64_t v = 1, ms;
+
+		/* Wait for all to be ready */
+		while (__atomic_load_n(&ctx.ready, __ATOMIC_ACQUIRE) !=
+		       ARRAY_SIZE(ctx.evfd))
+			;
+
+		/* Steady, go */
+		__atomic_fetch_sub(&ctx.ready, ARRAY_SIZE(ctx.evfd),
+				   __ATOMIC_ACQUIRE);
+
+		/* Wait all have gone to kernel */
+		while (count_waiters(&ctx) != ARRAY_SIZE(ctx.evfd))
+			;
+
+		/* 1ms should be enough to schedule away */
+		usleep(1000);
+
+		/* Quickly signal all handles at once */
+		for (n = 0; n < ARRAY_SIZE(ctx.evfd); n++) {
+			ret = write(ctx.evfd[n], &v, sizeof(v));
+			ASSERT_EQ(ret, sizeof(v));
+		}
+
+		/* Busy loop for 1s and wait for all waiters to wake up */
+		ms = msecs();
+		while (count_waiters(&ctx) && msecs() < ms + 1000)
+			;
+
+		ASSERT_EQ(count_waiters(&ctx), 0);
+	}
+	ctx.stopped = 1;
+	/* Stop waiters */
+	for (i = 0; i < ARRAY_SIZE(waiters); i++)
+		ret = pthread_kill(waiters[i], SIGUSR1);
+	for (i = 0; i < ARRAY_SIZE(waiters); i++)
+		pthread_join(waiters[i], NULL);
+
+	for (i = 0; i < ARRAY_SIZE(waiters); i++)
+		close(ctx.evfd[i]);
+	close(ctx.epfd);
+}
+
+struct epoll61_ctx {
+	int epfd;
+	int evfd;
+};
+
+static void *epoll61_write_eventfd(void *ctx_)
+{
+	struct epoll61_ctx *ctx = ctx_;
+	int64_t l = 1;
+
+	usleep(10950);
+	write(ctx->evfd, &l, sizeof(l));
+	return NULL;
+}
+
+static void *epoll61_epoll_with_timeout(void *ctx_)
+{
+	struct epoll61_ctx *ctx = ctx_;
+	struct epoll_event events[1];
+	int n;
+
+	n = epoll_wait(ctx->epfd, events, 1, 11);
+	/*
+	 * If epoll returned the eventfd, write on the eventfd to wake up the
+	 * blocking poller.
+	 */
+	if (n == 1) {
+		int64_t l = 1;
+
+		write(ctx->evfd, &l, sizeof(l));
+	}
+	return NULL;
+}
+
+static void *epoll61_blocking_epoll(void *ctx_)
+{
+	struct epoll61_ctx *ctx = ctx_;
+	struct epoll_event events[1];
+
+	epoll_wait(ctx->epfd, events, 1, -1);
+	return NULL;
+}
+
+TEST(epoll61)
+{
+	struct epoll61_ctx ctx;
+	struct epoll_event ev;
+	int i, r;
+
+	ctx.epfd = epoll_create1(0);
+	ASSERT_GE(ctx.epfd, 0);
+	ctx.evfd = eventfd(0, EFD_NONBLOCK);
+	ASSERT_GE(ctx.evfd, 0);
+
+	ev.events = EPOLLIN | EPOLLET | EPOLLERR | EPOLLHUP;
+	ev.data.ptr = NULL;
+	r = epoll_ctl(ctx.epfd, EPOLL_CTL_ADD, ctx.evfd, &ev);
+	ASSERT_EQ(r, 0);
+
+	/*
+	 * We are testing a race.  Repeat the test case 1000 times to make it
+	 * more likely to fail in case of a bug.
+	 */
+	for (i = 0; i < 1000; i++) {
+		pthread_t threads[3];
+		int n;
+
+		/*
+		 * Start 3 threads:
+		 * Thread 1 sleeps for 10.9ms and writes to the evenfd.
+		 * Thread 2 calls epoll with a timeout of 11ms.
+		 * Thread 3 calls epoll with a timeout of -1.
+		 *
+		 * The eventfd write by Thread 1 should either wakeup Thread 2
+		 * or Thread 3.  If it wakes up Thread 2, Thread 2 writes on the
+		 * eventfd to wake up Thread 3.
+		 *
+		 * If no events are missed, all three threads should eventually
+		 * be joinable.
+		 */
+		ASSERT_EQ(pthread_create(&threads[0], NULL,
+					 epoll61_write_eventfd, &ctx), 0);
+		ASSERT_EQ(pthread_create(&threads[1], NULL,
+					 epoll61_epoll_with_timeout, &ctx), 0);
+		ASSERT_EQ(pthread_create(&threads[2], NULL,
+					 epoll61_blocking_epoll, &ctx), 0);
+
+		for (n = 0; n < ARRAY_SIZE(threads); ++n)
+			ASSERT_EQ(pthread_join(threads[n], NULL), 0);
+	}
+
+	close(ctx.epfd);
+	close(ctx.evfd);
+}
+
+/* Equivalent to basic test epoll1, but exercising epoll_pwait2. */
+TEST(epoll62)
+{
+	int efd;
+	int sfd[2];
+	struct epoll_event e;
+
+	ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);
+
+	efd = epoll_create(1);
+	ASSERT_GE(efd, 0);
+
+	e.events = EPOLLIN;
+	ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);
+
+	ASSERT_EQ(write(sfd[1], "w", 1), 1);
+
+	EXPECT_EQ(sys_epoll_pwait2(efd, &e, 1, NULL, NULL, 0), 1);
+	EXPECT_EQ(sys_epoll_pwait2(efd, &e, 1, NULL, NULL, 0), 1);
+
+	close(efd);
+	close(sfd[0]);
+	close(sfd[1]);
+}
+
+/* Epoll_pwait2 basic timeout test. */
+TEST(epoll63)
+{
+	const int cfg_delay_ms = 10;
+	unsigned long long tdiff;
+	struct __kernel_timespec ts;
+	int efd;
+	int sfd[2];
+	struct epoll_event e;
+
+	ASSERT_EQ(socketpair(AF_UNIX, SOCK_STREAM, 0, sfd), 0);
+
+	efd = epoll_create(1);
+	ASSERT_GE(efd, 0);
+
+	e.events = EPOLLIN;
+	ASSERT_EQ(epoll_ctl(efd, EPOLL_CTL_ADD, sfd[0], &e), 0);
+
+	ts.tv_sec = 0;
+	ts.tv_nsec = cfg_delay_ms * 1000 * 1000;
+
+	tdiff = msecs();
+	EXPECT_EQ(sys_epoll_pwait2(efd, &e, 1, &ts, NULL, 0), 0);
+	tdiff = msecs() - tdiff;
+
+	EXPECT_GE(tdiff, cfg_delay_ms);
+
+	close(efd);
+	close(sfd[0]);
+	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