[PATCH 5.15.y 2/2] power: supply: charger-manager: register regulators before exposing sysfs
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From: Sasha Levin <sashal@kernel.org>
Date: 2026-09-09 11:03:56
Subsystem:
power supply class/subsystem and drivers, the rest · Maintainers:
Sebastian Reichel, Linus Torvalds
From: Fan Wu <redacted>
[ Upstream commit c57cb36f76eb7ced45f57af1a890d8f3a6d76342 ]
charger_manager_remove() and the err_reg_extcon probe error path free each
charger regulator with regulator_put() before tearing down the power_supply
sysfs entries (power_supply_unregister()). charger_manager_remove() also
calls try_charger_enable(cm, false) after the regulator_put() loop. A
concurrent write to a charger's externally_control sysfs attribute that
lands between regulator_put() and power_supply_unregister() can run
charger_externally_control_store() and call try_charger_enable(), which,
when charging is enabled, dereferences the already-freed consumer handle.
When charging is enabled, try_charger_enable(cm, false) in .remove() also
dereferences the freed handles directly. Both leave use-after-free windows.
Symmetrically, probe registers the sysfs entries (power_supply_register)
before acquiring the regulators (regulator_get, inside
charger_manager_register_extcon), so userspace can reach externally_control
before the regulators are available.
Split charger_manager_register_extcon() on the sync/async boundary:
charger_manager_get_regulators() (regulator_get only, no async producer)
now runs before power_supply_register() so sysfs is not live before
regulators are available, and charger_manager_register_extcon() keeps only
the extcon notifier/work setup, still after power_supply_register() so a
power_supply_register() failure cannot reach extcon setup. This keeps the
sysfs setup/teardown ordering symmetric without introducing an asynchronous
producer on the earlier probe-error path.
Move power_supply_unregister() and try_charger_enable(cm, false) ahead of
the regulator_put() loop on both teardown paths, and adjust err_reg_extcon
(power_supply_unregister() then fall through err_regulator for
regulator_put(); get_regulators self-rolls back on its own failure).
This does not address the separate extcon-notifier-driven deref of the same
handles, which needs its own synchronization design.
Found by an in-house static analysis tool.
Fixes: 3950c7865cd7 ("charger-manager: Add support sysfs entry for charger")
Cc: stable@vger.kernel.org
Assisted-by: Codex:gpt-5.6
Signed-off-by: Fan Wu <redacted>
Link: https://patch.msgid.link/20260728030123.230202-1-fanwu01@zju.edu.cn
Signed-off-by: Sebastian Reichel <redacted>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/power/supply/charger-manager.c | 54 +++++++++++++++++++-------
1 file changed, 39 insertions(+), 15 deletions(-)
diff --git a/drivers/power/supply/charger-manager.c b/drivers/power/supply/charger-manager.c
index a20e7aaffbaa8..7f7ddecf2250b 100644
--- a/drivers/power/supply/charger-manager.c
+++ b/drivers/power/supply/charger-manager.c@@ -1017,6 +1017,29 @@ static int charger_extcon_init(struct charger_manager *cm, return 0; } +static int charger_manager_get_regulators(struct charger_manager *cm) +{ + struct charger_desc *desc = cm->desc; + struct charger_regulator *charger; + int i, ret; + + for (i = 0; i < desc->num_charger_regulators; i++) { + charger = &desc->charger_regulators[i]; + charger->consumer = regulator_get(cm->dev, + charger->regulator_name); + if (IS_ERR(charger->consumer)) { + dev_err(cm->dev, "Cannot find charger(%s)\n", + charger->regulator_name); + ret = PTR_ERR(charger->consumer); + while (i-- > 0) + regulator_put(desc->charger_regulators[i].consumer); + return ret; + } + charger->cm = cm; + } + return 0; +} + /** * charger_manager_register_extcon - Register extcon device to receive state * of charger cable.
@@ -1039,15 +1062,6 @@ static int charger_manager_register_extcon(struct charger_manager *cm) for (i = 0; i < desc->num_charger_regulators; i++) { charger = &desc->charger_regulators[i]; - charger->consumer = regulator_get(cm->dev, - charger->regulator_name); - if (IS_ERR(charger->consumer)) { - dev_err(cm->dev, "Cannot find charger(%s)\n", - charger->regulator_name); - return PTR_ERR(charger->consumer); - } - charger->cm = cm; - for (j = 0; j < charger->num_cables; j++) { struct charger_cable *cable = &charger->cables[j];
@@ -1582,13 +1596,23 @@ static int charger_manager_probe(struct platform_device *pdev) } psy_cfg.attr_grp = desc->sysfs_groups; + /* + * Acquire charger regulators before exposing the sysfs entries, so + * userspace cannot reach externally_control before the regulators + * (and charger->cm) are available. Mirrors the order in remove(). + */ + ret = charger_manager_get_regulators(cm); + if (ret < 0) + return ret; + cm->charger_psy = power_supply_register(&pdev->dev, &cm->charger_psy_desc, &psy_cfg); if (IS_ERR(cm->charger_psy)) { dev_err(&pdev->dev, "Cannot register charger-manager with name \"%s\"\n", cm->charger_psy_desc.name); - return PTR_ERR(cm->charger_psy); + ret = PTR_ERR(cm->charger_psy); + goto err_regulator; } /* Register extcon device for charger cable */
@@ -1622,11 +1646,11 @@ static int charger_manager_probe(struct platform_device *pdev) return 0; err_reg_extcon: + power_supply_unregister(cm->charger_psy); +err_regulator: for (i = 0; i < desc->num_charger_regulators; i++) regulator_put(desc->charger_regulators[i].consumer); - power_supply_unregister(cm->charger_psy); - return ret; }
@@ -1644,12 +1668,12 @@ static void charger_manager_remove(struct platform_device *pdev) cancel_work_sync(&setup_polling); cancel_delayed_work_sync(&cm_monitor_work); - for (i = 0 ; i < desc->num_charger_regulators ; i++) - regulator_put(desc->charger_regulators[i].consumer); + try_charger_enable(cm, false); power_supply_unregister(cm->charger_psy); - try_charger_enable(cm, false); + for (i = 0 ; i < desc->num_charger_regulators ; i++) + regulator_put(desc->charger_regulators[i].consumer); } static const struct platform_device_id charger_manager_id[] = {
--
2.53.0