Messages in this thread | | | Subject | Re: [PATCH] regulator: core: avoid regulator_resolve_supply() race condition | From | Marek Szyprowski <> | Date | Thu, 21 Jan 2021 21:30:39 +0100 |
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Hi Mark,
On 21.01.2021 16:44, Mark Brown wrote: > On Thu, Jan 21, 2021 at 10:41:59AM +0100, Marek Szyprowski wrote: >> On 18.01.2021 21:49, Mark Brown wrote: >>> Does this help (completely untested): >> Sadly nope. I get same warning: > Try this instead: > > diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c > index 3ae5ccd9277d..31503776dbd7 100644 > --- a/drivers/regulator/core.c > +++ b/drivers/regulator/core.c > @@ -1823,17 +1823,6 @@ static int regulator_resolve_supply(struct regulator_dev *rdev) > if (rdev->supply) > return 0; > > - /* > - * Recheck rdev->supply with rdev->mutex lock held to avoid a race > - * between rdev->supply null check and setting rdev->supply in > - * set_supply() from concurrent tasks. > - */ > - regulator_lock(rdev); > - > - /* Supply just resolved by a concurrent task? */ > - if (rdev->supply) > - goto out; > - > r = regulator_dev_lookup(dev, rdev->supply_name); > if (IS_ERR(r)) { > ret = PTR_ERR(r); > @@ -1885,12 +1874,29 @@ static int regulator_resolve_supply(struct regulator_dev *rdev) > goto out; > } > > + /* > + * Recheck rdev->supply with rdev->mutex lock held to avoid a race > + * between rdev->supply null check and setting rdev->supply in > + * set_supply() from concurrent tasks. > + */ > + regulator_lock(rdev); > + > + /* Supply just resolved by a concurrent task? */ > + if (rdev->supply) { > + regulator_unlock(rdev); > + put_device(&r->dev); > + return ret; > + } > + > ret = set_supply(rdev, r); > if (ret < 0) { > + regulator_unlock(rdev); > put_device(&r->dev); > - goto out; > + return ret; > } > > + regulator_unlock(rdev); > + > /* > * In set_machine_constraints() we may have turned this regulator on > * but we couldn't propagate to the supply if it hadn't been resolved > @@ -1901,12 +1907,11 @@ static int regulator_resolve_supply(struct regulator_dev *rdev) > if (ret < 0) { > _regulator_put(rdev->supply); > rdev->supply = NULL; > - goto out; > + goto out_rdev_lock;
drivers/regulator/core.c:1910:4: error: label ‘out_rdev_lock’ used but not defined
> } > } > > out: > - regulator_unlock(rdev); > return ret; > } >
It looks that it finally fixes the locking issue, with the above goto removed completely to fix build. Feel free to add:
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Best regards
-- Marek Szyprowski, PhD Samsung R&D Institute Poland
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