Re: usb: does USBMALLOC_ZERO work correctly?

[sc dying <sc.dying%gmail.com@localhost>]

Thank you for fixing the problem.

On Thu, May 27, 2021 at 9:19 PM Jared McNeill <jmcneill%invisible.ca@localhost> wrote:
>
> Good catch! I've committed a slightly modified version of your patch.
>
> Take care,
> Jared
>
>
> On Thu, 27 May 2021, sc.dying%gmail.com@localhost wrote:
>
> > hi,
> >
> > sometimes memories allocated by usb_allocmem with USBMALLOC_ZERO
> > are not cleared.
> > usb_block_allocmem, called from usb_allocmem, returns with valid dmap
> > if it has found a block in usb_blk_freelist. In that path memset is not done.
> >
> >
> > --- src/sys/dev/usb/usb_mem.c.orig    2021-01-05 22:12:39.913414469 +0000
> > +++ src/sys/dev/usb/usb_mem.c 2021-05-27 01:36:53.189148366 +0000
> > @@ -135,6 +135,11 @@ usb_block_allocmem(bus_dma_tag_t tag, si
> >                       usb_blk_nfree--;
> >                       *dmap = b;
> >                       DPRINTFN(6, "free list size=%ju", b->size, 0, 0, 0);
> > +                     if ((flags & USBMALLOC_ZERO) != 0) {
> > +                             memset(b->kaddr, 0, b->size);
> > +                             bus_dmamap_sync(b->tag, b->map, 0, b->size,
> > +                                 BUS_DMASYNC_PREWRITE);
> > +                     }
> >                       return 0;
> >               }
> >       }
> >
> >