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From: Maxim Korotkov <korotkov.maxim.s@gmail.com>
To: Tony Lindgren <tony@atomide.com>
Cc: Maxim Korotkov <korotkov.maxim.s@gmail.com>,
	Haojian Zhuang <haojian.zhuang@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	"Manjunathappa, Prakash" <prakash.pm@ti.com>,
	linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	lvc-project@linuxtesting.org
Subject: [PATCH] pinctrl: single: Fix potential division by zero
Date: Thu, 17 Nov 2022 15:30:34 +0300	[thread overview]
Message-ID: <20221117123034.27383-1-korotkov.maxim.s@gmail.com> (raw)

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(-)

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 {
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: Maxim Korotkov <korotkov.maxim.s@gmail.com>
To: Tony Lindgren <tony@atomide.com>
Cc: Maxim Korotkov <korotkov.maxim.s@gmail.com>,
	Haojian Zhuang <haojian.zhuang@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	"Manjunathappa, Prakash" <prakash.pm@ti.com>,
	linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org,
	lvc-project@linuxtesting.org
Subject: [PATCH] pinctrl: single: Fix potential division by zero
Date: Thu, 17 Nov 2022 15:30:34 +0300	[thread overview]
Message-ID: <20221117123034.27383-1-korotkov.maxim.s@gmail.com> (raw)

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(-)

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 {
-- 
2.17.1


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             reply	other threads:[~2022-11-17 12:33 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-17 12:30 Maxim Korotkov [this message]
2022-11-17 12:30 ` [PATCH] pinctrl: single: Fix potential division by zero Maxim Korotkov
2022-11-18  8:15 ` Tony Lindgren
2022-11-18  8:15   ` Tony Lindgren
2022-11-21 13:42 ` Linus Walleij
2022-11-21 13:42   ` Linus Walleij

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