From: Mark Brown <broonie@kernel.org>
To: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: David Collins <collinsd@codeaurora.org>,
Liam Girdwood <lgirdwood@gmail.com>,
Krzysztof Kozlowski <krzk@kernel.org>,
Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
'Linux Samsung SOC' <linux-samsung-soc@vger.kernel.org>
Subject: Re: [PATCH] regulator: core: avoid regulator_resolve_supply() race condition
Date: Thu, 21 Jan 2021 15:44:18 +0000 [thread overview]
Message-ID: <20210121154418.GE4588@sirena.org.uk> (raw)
In-Reply-To: <5f37ae96-c5f9-6619-d88f-21c5e483ff8e@samsung.com>
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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;
}
}
out:
- regulator_unlock(rdev);
return ret;
}
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next prev parent reply other threads:[~2021-01-21 15:46 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 1:16 [PATCH] regulator: core: avoid regulator_resolve_supply() race condition David Collins
2021-01-11 16:28 ` Mark Brown
[not found] ` <CGME20210112213419eucas1p24231e4d0ac11c31184f2f8f3f20cbd9d@eucas1p2.samsung.com>
2021-01-12 21:34 ` Marek Szyprowski
2021-01-18 11:41 ` Naresh Kamboju
2021-01-18 20:49 ` Mark Brown
2021-01-21 9:41 ` Marek Szyprowski
2021-01-21 15:44 ` Mark Brown [this message]
2021-01-21 20:30 ` Marek Szyprowski
2021-01-23 1:54 ` David Collins
2021-03-01 19:59 ` patchwork-bot+linux-arm-msm
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