[PATCH 0/4] tree-wide: fix comparison to bitshift when dealing with a mask

Julia Lawall julia.lawall at lip6.fr
Tue Feb 6 06:08:21 PST 2018



On Tue, 6 Feb 2018, Dan Carpenter wrote:

> That found 4 that I think Wolfram's grep missed.
>
>  arch/um/drivers/vector_user.h             |    2 --
>  drivers/gpu/drm/mxsfb/mxsfb_regs.h        |    2 --
>  drivers/video/fbdev/mxsfb.c               |    2 --
>  include/drm/drm_scdc_helper.h             |    3 ---
>
> But it didn't find the two bugs that Geert found where the right side
> wasn't a number literal.
>
> drivers/net/can/m_can/m_can.c:#define RXFC_FWM_MASK     (0x7f < RXFC_FWM_SHIFT)

OK, I can easily add this in - I've got rules to protect against reporting
it at the moment.  It may end up with false positives.

> drivers/usb/gadget/udc/goku_udc.h:#define INT_EPnNAK(n) (0x00100 < (n))         /* 0 < n < 4 */

This is indeed harder, because one has to look at the usage site.

julia



More information about the linux-arm-kernel mailing list