linux-kernel - [PATCH AUTOSEL 6.0 39/77] regulator: core: Prevent integer underflow

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Message-Id: <20221009220754.1214186-39-sashal@kernel.org>
Date:   Sun,  9 Oct 2022 18:07:16 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Patrick Rudolph <patrick.rudolph@...ements.com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>, lgirdwood@...il.com
Subject: [PATCH AUTOSEL 6.0 39/77] regulator: core: Prevent integer underflow

From: Patrick Rudolph <patrick.rudolph@...ements.com>

[ Upstream commit 8d8e16592022c9650df8aedfe6552ed478d7135b ]

By using a ratio of delay to poll_enabled_time that is not integer
time_remaining underflows and does not exit the loop as expected.
As delay could be derived from DT and poll_enabled_time is defined
in the driver this can easily happen.

Use a signed iterator to make sure that the loop exits once
the remaining time is negative.

Signed-off-by: Patrick Rudolph <patrick.rudolph@...ements.com>
Link: https://lore.kernel.org/r/20220909125954.577669-1-patrick.rudolph@9elements.com
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/regulator/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index d3e8dc32832d..c3871565fd7d 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2681,7 +2681,7 @@ static int _regulator_do_enable(struct regulator_dev *rdev)
 	 * return -ETIMEDOUT.
 	 */
 	if (rdev->desc->poll_enabled_time) {
-		unsigned int time_remaining = delay;
+		int time_remaining = delay;
 
 		while (time_remaining > 0) {
 			_regulator_delay_helper(rdev->desc->poll_enabled_time);
-- 
2.35.1