Index: lib/libc/sys/poll.2
===================================================================
--- lib/libc/sys/poll.2
+++ lib/libc/sys/poll.2
@@ -28,7 +28,7 @@
 .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd November 13, 2014
+.Dd October 23, 2018
 .Dt POLL 2
 .Os
 .Sh NAME
@@ -232,7 +232,15 @@
 A signal was delivered before the time limit expired and
 before any of the selected events occurred.
 .It Bq Er EINVAL
-The specified time limit is invalid. One of its components is negative or too large.
+The specified time limit is invalid.
+One of its components is negative or too large.
+.It Bq Er EINVAL
+The number of pollfd structures specified by
+.Fa nfds
+exceeds the system tunable
+.Va kern.maxfilesperproc
+(and on systems where that tunable is set very low, exceeds
+.Dv FD_SETSIZE ) .
 .El
 .Sh SEE ALSO
 .Xr accept 2 ,
Index: sys/kern/sys_generic.c
===================================================================
--- sys/kern/sys_generic.c
+++ sys/kern/sys_generic.c
@@ -1339,6 +1339,13 @@
 	} else
 		sbt = -1;
 
+	/*
+	 * This is kinda bogus.  We have fd limits, but that is not
+	 * really related to the size of the pollfd array.  Make sure
+	 * we let the process use at least FD_SETSIZE entries and at
+	 * least enough for the system-wide limits.  We want to be reasonably
+	 * safe, but not overly restrictive.
+	 */
 	if (nfds > maxfilesperproc && nfds > FD_SETSIZE) 
 		return (EINVAL);
 	if (nfds > nitems(stackfds))