6.8-stable review patch. If anyone has any objections, please let me know.
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From: Hans de Goede hdegoede@redhat.com
[ Upstream commit bf6e4ee5c43690e4c5a8a057bbcd4ff986bed052 ]
The power_supply frame-work is not really designed for there to be long living in kernel references to power_supply devices.
Specifically unregistering a power_supply while some other code has a reference to it triggers a WARN in power_supply_unregister():
WARN_ON(atomic_dec_return(&psy->use_cnt));
Folllowed by the power_supply still getting removed and the backing data freed anyway, leaving the tusb1210 charger-detect code with a dangling reference, resulting in a crash the next time tusb1210_get_online() is called.
Fix this by only holding the reference in tusb1210_get_online() freeing it at the end of the function. Note this still leaves a theoretical race window, but it avoids the issue when manually rmmod-ing the charger chip driver during development.
Fixes: 48969a5623ed ("phy: ti: tusb1210: Add charger detection") Signed-off-by: Hans de Goede hdegoede@redhat.com Link: https://lore.kernel.org/r/20240406140821.18624-1-hdegoede@redhat.com Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/phy/ti/phy-tusb1210.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/phy/ti/phy-tusb1210.c b/drivers/phy/ti/phy-tusb1210.c index b4881cb344759..c23eecc7d1800 100644 --- a/drivers/phy/ti/phy-tusb1210.c +++ b/drivers/phy/ti/phy-tusb1210.c @@ -65,7 +65,6 @@ struct tusb1210 { struct delayed_work chg_det_work; struct notifier_block psy_nb; struct power_supply *psy; - struct power_supply *charger; #endif };
@@ -231,19 +230,24 @@ static const char * const tusb1210_chargers[] = {
static bool tusb1210_get_online(struct tusb1210 *tusb) { + struct power_supply *charger = NULL; union power_supply_propval val; - int i; + bool online = false; + int i, ret;
- for (i = 0; i < ARRAY_SIZE(tusb1210_chargers) && !tusb->charger; i++) - tusb->charger = power_supply_get_by_name(tusb1210_chargers[i]); + for (i = 0; i < ARRAY_SIZE(tusb1210_chargers) && !charger; i++) + charger = power_supply_get_by_name(tusb1210_chargers[i]);
- if (!tusb->charger) + if (!charger) return false;
- if (power_supply_get_property(tusb->charger, POWER_SUPPLY_PROP_ONLINE, &val)) - return false; + ret = power_supply_get_property(charger, POWER_SUPPLY_PROP_ONLINE, &val); + if (ret == 0) + online = val.intval; + + power_supply_put(charger);
- return val.intval; + return online; }
static void tusb1210_chg_det_work(struct work_struct *work) @@ -467,9 +471,6 @@ static void tusb1210_remove_charger_detect(struct tusb1210 *tusb) cancel_delayed_work_sync(&tusb->chg_det_work); power_supply_unregister(tusb->psy); } - - if (tusb->charger) - power_supply_put(tusb->charger); } #else static void tusb1210_probe_charger_detect(struct tusb1210 *tusb) { }