The patch regulator: core: Don't use regulators as supplies until the parent is bound has been applied to the regulator tree at git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark >From 66d228a2bf03b163ddaeca5f24f1ff89a84ad668 Mon Sep 17 00:00:00 2001 From: Jon Hunter <jonathanh@xxxxxxxxxx> Date: Wed, 11 Jan 2017 17:44:25 +0000 Subject: [PATCH] regulator: core: Don't use regulators as supplies until the parent is bound When regulators are successfully registered, we check to see if the regulator is a supply for any other registered regulator and if so add the new regulator as the supply for the existing regulator(s). Some devices, such as Power Management ICs, may register a series of regulators when probed and there are cases where one of the regulators may fail to register and defer the probing of the parent device. In this case any successfully registered regulators would be unregistered so that they can be re-registered at some time later when the probe is attempted again. However, if one of the regulators that was registered was added as a supply to another registered regulator (that did not belong to the same parent device), then this supply regulator was unregister again because the parent device is probe deferred, then a regulator could be holding an invalid reference to a supply regulator that has been unregistered. This will lead to a system crash if that regulator is then used. Although it would be possible to check when unregistering a regulator if any other regulator in the system is using it as a supply, it still may not be possible to remove it as a supply if this other regulator is in use. Therefore, fix this by preventing any regulator from adding another regulator as a supply if the parent device for the supply regulator has not been bound and if the parent device for the supply and the regulator are different. This will allow a parent device that is registering regulators to be probe deferred and ensure that none of the regulators it has registered are used as supplies for any other regulator from another device. Signed-off-by: Jon Hunter <jonathanh@xxxxxxxxxx> Signed-off-by: Mark Brown <broonie@xxxxxxxxxx> --- drivers/regulator/core.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 04baac9a165b..bcf67abd1cd2 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1553,6 +1553,19 @@ static int regulator_resolve_supply(struct regulator_dev *rdev) } } + /* + * If the supply's parent device is not the same as the + * regulator's parent device, then ensure the parent device + * is bound before we resolve the supply, in case the parent + * device get probe deferred and unregisters the supply. + */ + if (r->dev.parent && r->dev.parent != rdev->dev.parent) { + if (!device_is_bound(r->dev.parent)) { + put_device(&r->dev); + return -EPROBE_DEFER; + } + } + /* Recursively resolve the supply of the supply */ ret = regulator_resolve_supply(r); if (ret < 0) { -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html