The following diff should fix it. - todd
Index: sys/miscfs/fifofs/fifo_vnops.c =================================================================== RCS file: /home/cvs/openbsd/src/sys/miscfs/fifofs/fifo_vnops.c,v retrieving revision 1.41 diff -u -r1.41 fifo_vnops.c --- sys/miscfs/fifofs/fifo_vnops.c 14 Sep 2014 14:17:26 -0000 1.41 +++ sys/miscfs/fifofs/fifo_vnops.c 6 Oct 2014 22:51:50 -0000 @@ -147,8 +147,8 @@ return (error); } fip->fi_readers = fip->fi_writers = 0; + wso->so_state |= SS_CANTSENDMORE; wso->so_snd.sb_lowat = PIPE_BUF; - rso->so_state |= SS_CANTRCVMORE; } if (ap->a_mode & FREAD) { fip->fi_readers++; @@ -287,24 +287,12 @@ { struct vop_poll_args *ap = v; struct file filetmp; - short ostate; int revents = 0; if (ap->a_events & (POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND)) { - /* - * Socket and FIFO poll(2) semantics differ wrt EOF on read. - * Unlike a normal socket, FIFOs don't care whether or not - * SS_CANTRCVMORE is set. To get the correct semantics we - * must clear SS_CANTRCVMORE from so_state temporarily. - */ - ostate = ap->a_vp->v_fifoinfo->fi_readsock->so_state; - if (ap->a_events & (POLLIN | POLLRDNORM)) - ap->a_vp->v_fifoinfo->fi_readsock->so_state &= - ~SS_CANTRCVMORE; filetmp.f_data = ap->a_vp->v_fifoinfo->fi_readsock; if (filetmp.f_data) revents |= soo_poll(&filetmp, ap->a_events, ap->a_p); - ap->a_vp->v_fifoinfo->fi_readsock->so_state = ostate; } if (ap->a_events & (POLLOUT | POLLWRNORM | POLLWRBAND)) { filetmp.f_data = ap->a_vp->v_fifoinfo->fi_writesock;