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authorArnd Bergmann <arnd@arndb.de>2015-11-27 14:46:41 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-05-04 14:48:50 -0700
commitf500da32a1663c1bb2587ff04be08d5220b3afca (patch)
tree3e8715902654b292f9ff86b7601237725bc88f01 /drivers/regulator
parent34af67eb941ae5371110c9adbd5392c7a3aa841e (diff)
regulator: core: fix regulator_lock_supply regression
commit bb41897e38c53458a88b271f2fbcd905ee1f9584 upstream. As noticed by Geert Uytterhoeven, my patch to avoid a harmless build warning in regulator_lock_supply() was total crap and introduced a real bug: > [ BUG: bad unlock balance detected! ] > kworker/u4:0/6 is trying to release lock (&rdev->mutex) at: > [<c0247b84>] regulator_set_voltage+0x38/0x50 we still lock the regulator supplies, but not the actual regulators, so we are missing a lock, and the unlock is unbalanced. This rectifies it by first locking the regulator device itself before using the same loop as before to lock its supplies. Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Fixes: 716fec9d1965 ("[SUBMITTED] regulator: core: avoid unused variable warning") Signed-off-by: Mark Brown <broonie@kernel.org> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/regulator')
-rw-r--r--drivers/regulator/core.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index c70017d5f74b..daffff83ced2 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -140,7 +140,8 @@ static void regulator_lock_supply(struct regulator_dev *rdev)
{
int i;
- for (i = 0; rdev->supply; rdev = rdev->supply->rdev, i++)
+ mutex_lock(&rdev->mutex);
+ for (i = 1; rdev->supply; rdev = rdev->supply->rdev, i++)
mutex_lock_nested(&rdev->mutex, i);
}