regulator: core: Prevent integer underflow

[ 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@9elements.com>
Link: https://lore.kernel.org/r/20220909125954.577669-1-patrick.rudolph@9elements.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 43613db..aa4d78b 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2636,7 +2636,7 @@ static int _regulator_do_enable(struct regulator_dev *rdev)
         * expired, return -ETIMEDOUT.
         */
        if (rdev->desc->poll_enabled_time) {
-               unsigned int time_remaining = delay;
+               int time_remaining = delay;
 
                while (time_remaining > 0) {
                        _regulator_enable_delay(rdev->desc->poll_enabled_time);