diff mbox series

pinctrl: single: Fix potential division by zero

Message ID 20221117123034.27383-1-korotkov.maxim.s@gmail.com
State New
Headers
Series pinctrl: single: Fix potential division by zero |

Commit Message

Maxim Korotkov Nov. 17, 2022, 12:30 p.m. UTC 
  There is a possibility of dividing by zero due to the pcs->bits_per_pin
if pcs->fmask() also has a value of zero and called fls
from asm-generic/bitops/builtin-fls.h or arch/x86/include/asm/bitops.h.
The function pcs_probe() has the branch that assigned to fmask 0 before
pcs_allocate_pin_table() was called

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 4e7e8017a80e ("pinctrl: pinctrl-single: enhance to configure multiple pins of different modules")
Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
---
 drivers/pinctrl/pinctrl-single.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Tony Lindgren Nov. 18, 2022, 8:15 a.m. UTC | #1 
* Maxim Korotkov <korotkov.maxim.s@gmail.com> [221117 12:22]:
> There is a possibility of dividing by zero due to the pcs->bits_per_pin
> if pcs->fmask() also has a value of zero and called fls
> from asm-generic/bitops/builtin-fls.h or arch/x86/include/asm/bitops.h.
> The function pcs_probe() has the branch that assigned to fmask 0 before
> pcs_allocate_pin_table() was called

Reviewed-by: Tony Lindgren <tony@atomide.com>
Linus Walleij Nov. 21, 2022, 1:42 p.m. UTC | #2 
On Thu, Nov 17, 2022 at 1:32 PM Maxim Korotkov
<korotkov.maxim.s@gmail.com> wrote:

> There is a possibility of dividing by zero due to the pcs->bits_per_pin
> if pcs->fmask() also has a value of zero and called fls
> from asm-generic/bitops/builtin-fls.h or arch/x86/include/asm/bitops.h.
> The function pcs_probe() has the branch that assigned to fmask 0 before
> pcs_allocate_pin_table() was called
>
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>
> Fixes: 4e7e8017a80e ("pinctrl: pinctrl-single: enhance to configure multiple pins of different modules")
> Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>

Patch applied for fixes.

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/pinctrl/pinctrl-single.c b/drivers/pinctrl/pinctrl-single.c
index 67bec7ea0f8b..414ee6bb8ac9 100644
--- a/drivers/pinctrl/pinctrl-single.c
+++ b/drivers/pinctrl/pinctrl-single.c
@@ -727,7 +727,7 @@  static int pcs_allocate_pin_table(struct pcs_device *pcs)
 
 	mux_bytes = pcs->width / BITS_PER_BYTE;
 
-	if (pcs->bits_per_mux) {
+	if (pcs->bits_per_mux && pcs->fmask) {
 		pcs->bits_per_pin = fls(pcs->fmask);
 		nr_pins = (pcs->size * BITS_PER_BYTE) / pcs->bits_per_pin;
 	} else {