[merged] kselftest-introduce-new-epoll-test-case.patch removed from -mm tree

[merged] kselftest-introduce-new-epoll-test-case.patch removed from -mm tree

[akpm]

The patch titled
     Subject: kselftest: introduce new epoll test case
has been removed from the -mm tree.  Its filename was
     kselftest-introduce-new-epoll-test-case.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Roman Penyaev <rpenyaev@suse.de>
Subject: kselftest: introduce new epoll test case

This testcase repeats epollbug.c from the bug:

  https://bugzilla.kernel.org/show_bug.cgi?id=205933

What it tests?  It tests the race between epoll_ctl() and epoll_wait(). 
New event mask passed to epoll_ctl() triggers wake up, which can be missed
because of the bug described in the link.  Reproduction is 100%, so easy
to fix.  Kudos, Max, for wonderful test case.

Link: http://lkml.kernel.org/r/20200214170211.561524-2-rpenyaev@suse.de
Signed-off-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Max Neunhoeffer <max@arangodb.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Christopher Kohlhoff <chris.kohlhoff@clearpool.io>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Jes Sorensen <jes.sorensen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c |   67 +++++++++-
 1 file changed, 66 insertions(+), 1 deletion(-)

--- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c~kselftest-introduce-new-epoll-test-case
+++ a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c
@@ -7,13 +7,14 @@
 #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;
@@ -3071,4 +3072,68 @@ 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]);
+}
+
 TEST_HARNESS_MAIN
_

Patches currently in -mm which might be from rpenyaev@suse.de are

[merged] kselftest-introduce-new-epoll-test-case.patch removed from -mm tree

[akpm]

The patch titled
     Subject: kselftest: introduce new epoll test case
has been removed from the -mm tree.  Its filename was
     kselftest-introduce-new-epoll-test-case.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Davidlohr Bueso <dave@stgolabs.net>
Subject: 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>
---

 tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c |   44 ++++++++++
 1 file changed, 44 insertions(+)

--- a/tools/testing/selftests/filesystems/epoll/epoll_wakeup_test.c~kselftest-introduce-new-epoll-test-case
+++ a/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
_

Patches currently in -mm which might be from dave@stgolabs.net are