stress2: Added a regression test

tools/test/stress2/misc/kevent16.sh

@@ -0,0 +1,92 @@
+#!/bin/sh
+
+# Bug 258310 - kevent() does not see signal with zero timeout
+# Test scenario copied from the bug report.
+
+# Fixed by: 98168a6e6c12 - main - kqueue: drain kqueue taskqueue if syscall tickled it
+
+cat > /tmp/kevent16.c <<EOF
+#ifdef NDEBUG
+#undef NDEBUG
+#endif
+
+#define _GNU_SOURCE
+
+#include <sys/types.h>
+
+#include <sys/event.h>
+
+#include <assert.h>
+#include <errno.h>
+#include <signal.h>
+#include <stdlib.h>
+
+#include <poll.h>
+#include <unistd.h>
+
+int
+main(void)
+{
+	long l;
+	int rv;
+
+	sigset_t set;
+	rv = sigemptyset(&set);
+	assert(rv == 0);
+	rv = sigaddset(&set, SIGUSR1);
+	assert(rv == 0);
+
+	rv = sigprocmask(SIG_BLOCK, &set, NULL);
+	assert(rv == 0);
+
+	int skq = kqueue();
+	assert(skq >= 0);
+
+	struct kevent kev;
+	EV_SET(&kev, SIGUSR1, EVFILT_SIGNAL, EV_ADD, 0, 0, 0);
+	rv = kevent(skq, &kev, 1, NULL, 0, NULL);
+	assert(rv == 0);
+
+	int kq = kqueue();
+	assert(kq >= 0);
+
+	EV_SET(&kev, skq, EVFILT_READ, EV_ADD | EV_CLEAR, 0, 0, 0);
+	rv = kevent(kq, &kev, 1, NULL, 0, NULL);
+	assert(rv == 0);
+
+	for (l = 0; l < 1000000; l++) {
+		rv = kill(getpid(), SIGUSR1);
+		assert(rv == 0);
+
+		/* Turn this into `#if 1` to avoid the race. */
+#if 0
+		rv = kevent(kq, NULL, 0, &kev, 1, NULL);
+#else
+		rv = kevent(kq, NULL, 0, &kev, 1, &(struct timespec) { 0, 0 });
+#endif
+		assert(rv == 1);
+		rv = kevent(kq, NULL, 0, &kev, 1, &(struct timespec) { 0, 0 });
+		assert(rv == 0);
+
+		rv = kevent(skq, NULL, 0, &kev, 1, &(struct timespec) { 0, 0 });
+		assert(rv == 1);
+		rv = kevent(skq, NULL, 0, &kev, 1, &(struct timespec) { 0, 0 });
+		assert(rv == 0);
+
+		siginfo_t siginfo;
+
+		rv = sigtimedwait(&set, &siginfo, &(struct timespec) { 0, 0 });
+		assert(rv == SIGUSR1);
+
+		rv = sigtimedwait(&set, &siginfo, &(struct timespec) { 0, 0 });
+		assert(rv < 0);
+		assert(errno == EAGAIN);
+	}
+}
+EOF
+cc -o /tmp/kevent16 -Wall -Wextra -O2 /tmp/kevent16.c || exit 1
+
+/tmp/kevent16; s=$?
+
+rm -f /tmp/kevent16.c kevent16 kevent16.core
+exit $s