From: Dmitry Osipenko digetx@gmail.com
commit 0a7416f94707c60b9f66b01c0a505b7e41375f3a upstream.
The recent commit 7d8196641ee1 ("regulator: Remove pointer table overallocation") changed the size of coupled_rdevs and now KASAN is able to detect slab-out-of-bounds problem in regulator_unlock_recursive(), which is a legit problem caused by a typo in the code. The recursive unlock function uses n_coupled value of a parent regulator for unlocking supply regulator, while supply's n_coupled should be used. In practice problem may only affect platforms that use coupled regulators.
Cc: stable@vger.kernel.org # 5.0+ Fixes: f8702f9e4aa7 ("regulator: core: Use ww_mutex for regulators locking") Signed-off-by: Dmitry Osipenko digetx@gmail.com Link: https://lore.kernel.org/r/20200831204335.19489-1-digetx@gmail.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/regulator/core.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
--- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -235,8 +235,8 @@ static bool regulator_supply_is_couple(s static void regulator_unlock_recursive(struct regulator_dev *rdev, unsigned int n_coupled) { - struct regulator_dev *c_rdev; - int i; + struct regulator_dev *c_rdev, *supply_rdev; + int i, supply_n_coupled;
for (i = n_coupled; i > 0; i--) { c_rdev = rdev->coupling_desc.coupled_rdevs[i - 1]; @@ -244,10 +244,13 @@ static void regulator_unlock_recursive(s if (!c_rdev) continue;
- if (c_rdev->supply && !regulator_supply_is_couple(c_rdev)) - regulator_unlock_recursive( - c_rdev->supply->rdev, - c_rdev->coupling_desc.n_coupled); + if (c_rdev->supply && !regulator_supply_is_couple(c_rdev)) { + supply_rdev = c_rdev->supply->rdev; + supply_n_coupled = supply_rdev->coupling_desc.n_coupled; + + regulator_unlock_recursive(supply_rdev, + supply_n_coupled); + }
regulator_unlock(c_rdev); }