On 11/01/17 17:14, Jon Hunter wrote: > 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> > --- > > Changes since V1: > - Updated patch per Mark's input to only prevent resolving the supply > if the supply's parent is different from the regulator's and the > supply's parent device is not bound. > - Added comment. > > drivers/regulator/core.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c > index 04baac9a165b..00466a82c3ad 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. > + */ Ugh ... looks like I screwed up the formatting here. Also ... s/get/gets Resending ... Jon -- nvpublic -- 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
