On Tue, Jan 10, 2023 at 08:36:00PM +0530, Harshit Mogalapalli wrote:
>
> Hi Greg,
>
> On 24/10/22 5:04 pm, Greg Kroah-Hartman wrote:
> > From: Pavel Begunkov <asml.silence@xxxxxxxxx>
> >
> > [ upstream commit 62bb0647b14646fa6c9aa25ecdf67ad18f13523c ]
> >
>
> This commit 62bb0647b14646fa6c9aa25ecdf67ad18f13523 also changes second
> argument from unsigned to long.
>
> > Kernel test robot reports that we test negativity of an unsigned in
> > io_fixup_rw_res() after a recent change, which masks error codes and
> > messes up the return value in case I/O is re-retried and failed with
> > an error.
> >
> > Fixes: 4d9cb92ca41dd ("io_uring/rw: fix short rw error handling")
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
> > Link: https://lore.kernel.org/r/9754a0970af1861e7865f9014f735c70dc60bf79.1663071587.git.asml.silence@xxxxxxxxx
> > Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > ---
> > fs/io_uring.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > --- a/fs/io_uring.c
> > +++ b/fs/io_uring.c
> > @@ -2701,7 +2701,7 @@ static bool __io_complete_rw_common(stru
> > return false;
> > }
> > -static inline unsigned io_fixup_rw_res(struct io_kiocb *req, unsigned res)
> > +static inline int io_fixup_rw_res(struct io_kiocb *req, unsigned res)
> > {
>
> I think the res should be of type 'long'.
> I noticed this when I ran smatch on 5.10.y io_uring backport from 5.15.y
> patch.
>
> Smatch warning: io_fixup_rw_res() warn: unsigned 'res' is never less than
> zero.
>
> static inline int io_fixup_rw_res(struct io_kiocb *req, unsigned res)
> {
> struct io_async_rw *io = req->async_data;
>
> /* add previously done IO, if any */
> if (io && io->bytes_done > 0) {
> if (res < 0) //// unsigned comparison with zero.
> res = io->bytes_done;
> else
> res += io->bytes_done;
> }
> return res;
> }
>
> We don't have upstream commit to backport in this case. Should we fix this
> with no-upstream reference commit?
Just reference the commit that this fixes properly and that should be
fine, thanks for the review and catching this!
greg k-h
