> On Fri, Mar 16, 2012 at 02:15:29PM +1100, matthew green wrote:
> >
> > > Module Name: src
> > > Committed By: bouyer
> > > Date: Thu Mar 15 18:38:37 UTC 2012
> > >
> > > Modified Files:
> > > src/sys/dev/usb: ehci.c
> > >
> > > Log Message:
> > > Do not read array before detecting array overflow, found by gcc -O3
> >
> > hmmmm.
> >
> > seems like this should move the DIAG code to just the printf(). this
> > totally changes the behaviour of the failure mode as-is.
> >
> > we can detect an overflow here but let non-DIAG code fail.
>
> You mean, something like that:
>
> Index: ehci.c
> ===================================================================
> RCS file: /cvsroot/src/sys/dev/usb/ehci.c,v
> retrieving revision 1.188
> diff -u -p -u -r1.188 ehci.c
> --- ehci.c 15 Mar 2012 18:38:37 -0000 1.188
> +++ ehci.c 16 Mar 2012 07:50:28 -0000
> @@ -2712,12 +2712,12 @@ ehci_alloc_sqtd_chain(struct ehci_pipe *
> ehci_physaddr_t a = dataphys + i * EHCI_PAGE_SIZE;
> if (i != 0) /* use offset only in first buffer */
> a = EHCI_PAGE(a);
> -#ifdef DIAGNOSTIC
> if (i >= EHCI_QTD_NBUFFERS) {
> +#ifdef DIAGNOSTIC
> printf("ehci_alloc_sqtd_chain: i=%d\n", i);
> +#endif
> goto nomem;
> }
> -#endif
> cur->qtd.qtd_buffer[i] = htole32(a);
> cur->qtd.qtd_buffer_hi[i] = 0;
> }
>
> I agree it would be better.
> If you mean something else I don't understand :)
that is exactly what i mean. please commit :)
