Eric Lee / smarc-ti-linux-kernel

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Commit ba31c58d468aa22cc8b9ec0eb896b75a868e4bd1

Authored by Ashay Jaiswal
Committed by Greg Kroah-Hartman
1 parent 198bcce84a

regulator: core: fix race condition in regulator_put() 

commit 83b0302d347a49f951e904184afe57ac3723476e upstream.

The regulator framework maintains a list of consumer regulators
for a regulator device and protects it from concurrent access using
the regulator device's mutex lock.

In the case of regulator_put() the consumer is removed and regulator
device's parameters are updated without holding the regulator device's
mutex. This would lead to a race condition between the regulator_put()
and any function which traverses the consumer list or modifies regulator
device's parameters.
Fix this race condition by holding the regulator device's mutex in case
of regulator_put.

Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 3 additions and 1 deletions Side-by-side Diff

drivers/regulator/core.c
Diff comments   View file @ ba31c58
... ... @@ -1488,7 +1488,7 @@
1488 1488 }
1489 1489 EXPORT_SYMBOL_GPL(regulator_get_optional);
1490 1490  
1491   -/* Locks held by regulator_put() */
  1491 +/* regulator_list_mutex lock held by regulator_put() */
1492 1492 static void _regulator_put(struct regulator *regulator)
1493 1493 {
1494 1494 struct regulator_dev *rdev;
1495 1495  
... ... @@ -1503,12 +1503,14 @@
1503 1503 /* remove any sysfs entries */
1504 1504 if (regulator->dev)
1505 1505 sysfs_remove_link(&rdev->dev.kobj, regulator->supply_name);
  1506 + mutex_lock(&rdev->mutex);
1506 1507 kfree(regulator->supply_name);
1507 1508 list_del(&regulator->list);
1508 1509 kfree(regulator);
1509 1510  
1510 1511 rdev->open_count--;
1511 1512 rdev->exclusive = 0;
  1513 + mutex_unlock(&rdev->mutex);
1512 1514  
1513 1515 module_put(rdev->owner);
1514 1516 }