On Wed, 10 Jun 2009 17:30:07 -0400 (EDT), Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote:
> > + if (io->nents == io->entries && !PageHighMem(sg_page(sg))) {
> > + io->urbs[i]->transfer_buffer = sg_virt(sg);
> > + } else {
> > + io->urbs[i]->transfer_buffer = NULL;
> > + }
> > if (dma) {
....
> > } else {
> > /* hc may use _only_ transfer_buffer */
> > - io->urbs[i]->transfer_buffer = sg_virt(sg);
> > len = sg->length;
>
> There needs to be a test here for transfer_buffer != NULL. It would
> not be good for an HCD using PIO to crash the system because it tried
> to access invalid memory.
I do not understand what scenario we are considering that leads to
the crash. Are you talking about a PIO controller and a highmem system?
If yes, how does it work in the current code?
-- Pete
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