svn commit: r230583 - head/sys/kern
David Schultz
das at FreeBSD.ORG
Fri Jan 27 19:42:23 UTC 2012
On Fri, Jan 27, 2012, Kostik Belousov wrote:
> On Fri, Jan 27, 2012 at 07:50:30PM +1100, Bruce Evans wrote:
> > On Thu, 26 Jan 2012, Gleb Smirnoff wrote:
> >
> > >On Thu, Jan 26, 2012 at 11:53:57PM +1100, Bruce Evans wrote:
> > >B> > @@ -1552,6 +1552,12 @@ aio_aqueue(struct thread *td, struct aio
> > >B> > return (error);
> > >B> > }
> > >B> >
> > >B> > + /* XXX: aio_nbytes is later casted to signed types. */
> > >B> > + if ((int)aiocbe->uaiocb.aio_nbytes < 0) {
> > >B>
> > >B> This should avoid implementation-defined behaviour by checking if
> > >B>
> > >B> (uncast)aiocbe->uaiocb.aio_nbytes > INT_MAX.
> >
> > >Is the attached patch okay?
> >
> > Yes. It now matches the style used for read^Wsys_read() and friends.
> > This used to have to fit the count in "int uio_resid". uio_resid now
> > has type ssize_t, but for some reason the old INT_MAX limits remain.
>
> Well, I can revive the patch. I still think it is good to get rid of
> the limit.
The correct limit on the maximum size of a single read/write is
SSIZE_MAX, but FreeBSD uses INT_MAX. It's not safe to raise the
limit yet, though, because of bugs in several filesystems. For
example, FFS copies uio_resid into a local variable of type int.
I have some old patches that fix some of these issues for FFS and
cd9660, but surely there are more places I didn't notice.
By the way, PR 147226 is about this.
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