regulator: avoid resolve_supply() infinite recursion

commit 4b639e254d3d4f15ee4ff2b890a447204cfbeea9 upstream

When a regulator's name equals its supply's name the
regulator_resolve_supply() recurses indefinitely. Add a check
so that debugging the problem is easier. The "fixed" commit
just exposed the problem.

Fixes: aea6cb99703e ("regulator: resolve supply after creating regulator")
Cc: stable@vger.kernel.org
Reported-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Tested-by: Ahmad Fatoum <a.fatoum@pengutronix.de> # stpmic1
Link: https://lore.kernel.org/r/c6171057cfc0896f950c4d8cb82df0f9f1b89ad9.1605226675.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Mark Brown <broonie@kernel.org>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 0a0dd0aac047ce112e01eef1a5fb095dd675df76..89f14e301b4c14b16094125f532578b1ec53bcbb 100644 (file)
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1550,6 +1550,12 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
                }
        }
 
+       if (r == rdev) {
+               dev_err(dev, "Supply for %s (%s) resolved to itself\n",
+                       rdev->desc->name, rdev->supply_name);
+               return -EINVAL;
+       }
+
        /* Recursively resolve the supply of the supply */
        ret = regulator_resolve_supply(r);
        if (ret < 0) {