> @@ -495,51 +495,13 @@
   >  #endif
   >             ) {
   > -               sep = (struct swapent *)SCARG(uap, arg);
   > -               count = 0;
   > +               misc = MIN(uvmexp.nswapdev, misc);
   > +               len = sizeof(struct swapent) * misc;
   > +               sep = (struct swapent *)malloc(len, M_TEMP, M_WAITOK);
   >  
   > -               LIST_FOREACH(spp, &swap_priority, spi_swappri) {
   > -                       for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev);
   > -                            sdp != (void *)&spp->spi_swapdev && misc-- > 0;
   > -                            sdp = CIRCLEQ_NEXT(sdp, swd_next)) {
   > -                               /*
   > -                                * backwards compatibility for system call.
   > -                                * note that we use 'struct oswapent' as an
   > -                                * overlay into both 'struct swapdev' and
   > -                                * the userland 'struct swapent', as we
   > -                                * want to retain backwards compatibility
   > -                                * with NetBSD 1.3.
   > -                                */
   > -                               sdp->swd_ose.ose_inuse =
   > -                                   btodb((u_int64_t)sdp->swd_npginuse <<
   > -                                   PAGE_SHIFT);
   > -                               error = copyout(&sdp->swd_ose, sep,
   > -                                               sizeof(struct oswapent));
   > +               uvm_swap_stats(SCARG(uap, cmd), sep, misc, retval);
   > +               error = copyout(sep, (void *)SCARG(uap, arg), len);
   
   Does old 1.3 binary prepare `sizeof(struct swapent) * misc' bytes
   space?  I guess you should copyout up to the length just
   uvm_swap_stats() copied.


ah, well spotted enami.  perhaps change uvm_swap_stats() to return
a size_t length?


emmanuel, it would be really nice if you could get a 1.3 swapctl
binary and test with it, just to make sure.