From:   Zheng Wang <zyytlz.wz@163.com>
To:     njavali@marvell.com
Cc:     sebastian.reichel@collabora.com, mrangankar@marvell.com,
        GR-QLogic-Storage-Upstream@marvell.com, jejb@linux.ibm.com,
        martin.petersen@oracle.com, linux-scsi@vger.kernel.org,
        linux-kernel@vger.kernel.org, hackerzheng666@gmail.com,
        1395428693sheep@gmail.com, alex000young@gmail.com,
        Zheng Wang <zyytlz.wz@163.com>
Subject: [PATCH v2] power: supply: da9150: Fix use after free bug in  da9150_charger_remove due to race condition
Date:   Sun, 12 Mar 2023 01:46:50 +0800
Message-Id: <20230311174650.3979517-1-zyytlz.wz@163.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

In da9150_charger_probe, &charger->otg_work is bound with
da9150_charger_otg_work. da9150_charger_otg_ncb may be
called to start the work.

If we remove the module which will call da9150_charger_remove
to make cleanup, there may be a unfinished work. The possible
sequence is as follows:

Fix it by canceling the work before cleanup in the da9150_charger_remove

CPU0                  CPUc1

                    |da9150_charger_otg_work
da9150_charger_remove      |
power_supply_unregister  |
device_unregister   |
power_supply_dev_release|
kfree(psy)          |
                    |
                    | 	power_supply_changed(charger->usb);
                    |   //use

Fixes: c1a281e34dae ("power: Add support for DA9150 Charger")
Signed-off-by: Zheng Wang <zyytlz.wz@163.com>
---
v2:
- fix wrong description in commit message and mov cancel_work_sync
after usb_unregister_notifier suggested by Sebastian Reichel
---
 drivers/power/supply/da9150-charger.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/power/supply/da9150-charger.c b/drivers/power/supply/da9150-charger.c
index 14da5c595dd9..a87aeaea38e1 100644
--- a/drivers/power/supply/da9150-charger.c
+++ b/drivers/power/supply/da9150-charger.c
@@ -657,6 +657,7 @@ static int da9150_charger_remove(struct platform_device *pdev)
 
 	if (!IS_ERR_OR_NULL(charger->usb_phy))
 		usb_unregister_notifier(charger->usb_phy, &charger->otg_nb);
+	cancel_work_sync(&charger->otg_work);
 
 	power_supply_unregister(charger->battery);
 	power_supply_unregister(charger->usb);
-- 
2.25.1