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pinctrl: single: Fix potential division by zero

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[ Upstream commit 64c150339e7f6c5cbbe8c17a56ef2b3902612798 ]

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: 4e7e8017a8 ("pinctrl: pinctrl-single: enhance to configure multiple pins of different modules")
Signed-off-by: Maxim Korotkov <korotkov.maxim.s@gmail.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Link: https://lore.kernel.org/r/20221117123034.27383-1-korotkov.maxim.s@gmail.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Maxim Korotkov 2022-11-17 15:30:34 +03:00 committed by Greg Kroah-Hartman
parent 73dce3c1d4
commit 0090231df2
1 changed files with 1 additions and 1 deletions
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2
drivers/pinctrl/pinctrl-single.c
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@ -703,7 +703,7 @@ 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;
num_pins_in_register = pcs->width / pcs->bits_per_pin;