Re: [PATCH] USB: serial: io_edgeport: cap received transmit credits

[박선호]

You're right, I'll use it in v2.

Thanks,
Sunho

2026년 7월 14일 (화) 오후 6:38, Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>님이 작성:
>
> On Tue, Jul 14, 2026 at 06:34:24PM +0900, Sunho Park wrote:
> > The interrupt-status packet reports transmit credits returned by the
> > device. edge_interrupt_callback() adds the 16-bit value to txCredits
> > without checking maxTxCredits.
> >
> > edge_write() uses txCredits minus the software FIFO count as the amount
> > of data that fits. Since the FIFO is allocated with maxTxCredits bytes,
> > txCredits exceeding maxTxCredits can cause OOB write in ring buffer.
> >
> > Cap accumulated credits at maxTxCredits. Conforming devices should never
> > hit the cap.
> >
> > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Assisted-by: Codex:GPT-5
> > Signed-off-by: Sunho Park <shpark061104@xxxxxxxxx>
> > ---
> >  drivers/usb/serial/io_edgeport.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
> > index 34ccf7820537..503b3b5bb647 100644
> > --- a/drivers/usb/serial/io_edgeport.c
> > +++ b/drivers/usb/serial/io_edgeport.c
> > @@ -646,7 +646,10 @@ static void edge_interrupt_callback(struct urb *urb)
> >                               if (edge_port && edge_port->open) {
> >                                       spin_lock_irqsave(&edge_port->ep_lock,
> >                                                         flags);
> > -                                     edge_port->txCredits += txCredits;
> > +                                     edge_port->txCredits =
> > +                                             min_t(unsigned int,
>
> LLMs really love to use min_t() as they haven't been trained on modern
> kernel code.
>
> Please don't use it, it shouldn't be needed here, right?
>
> thanks,
>
> greg k-h