linux-kernel - [PATCH 4.4 232/312] power_supply: tps65217-charger: Fix NULL deref during property export

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Message-Id: <20200508123140.750024620@linuxfoundation.org>
Date:   Fri,  8 May 2020 14:33:43 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Marcin Niestroj <m.niestroj@...nn-global.com>,
        Sebastian Reichel <sre@...nel.org>
Subject: [PATCH 4.4 232/312] power_supply: tps65217-charger: Fix NULL deref during property export

From: Marcin Niestroj <m.niestroj@...nn-global.com>

commit 362761299eea7dfc3a4870551de36e08758b9254 upstream.

This bug leads to:

[    1.906411] Unable to handle kernel NULL pointer dereference at virtual address 0000000c
[    1.914878] pgd = c0004000
[    1.917786] [0000000c] *pgd=00000000
[    1.921536] Internal error: Oops: 5 [#1] SMP ARM
[    1.926357] Modules linked in:
[    1.929556] CPU: 0 PID: 14 Comm: kworker/0:1 Not tainted 4.4.5 #18
[    1.936006] Hardware name: Generic AM33XX (Flattened Device Tree)
[    1.942383] Workqueue: events power_supply_changed_work
[    1.947842] task: de2c41c0 ti: de2c8000 task.ti: de2c8000
[    1.953483] PC is at tps65217_ac_get_property+0x14/0x28
[    1.958937] LR is at tps65217_ac_get_property+0x10/0x28

Driver was trying to use drv_data in property get handler. However drv_data
was not set, so it caused NULL pointer dereference. This patch properly
sets drv_data during probe by power_supply_config parameter, so the
property get handler works as desired.

Signed-off-by: Marcin Niestroj <m.niestroj@...nn-global.com>
Fixes: 3636859b280c ("power_supply: Add support for tps65217-charger")
Signed-off-by: Sebastian Reichel <sre@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/power/tps65217_charger.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/drivers/power/tps65217_charger.c
+++ b/drivers/power/tps65217_charger.c
@@ -197,6 +197,7 @@ static int tps65217_charger_probe(struct
 {
 	struct tps65217 *tps = dev_get_drvdata(pdev->dev.parent);
 	struct tps65217_charger *charger;
+	struct power_supply_config cfg = {};
 	int ret;
 
 	dev_dbg(&pdev->dev, "%s\n", __func__);
@@ -209,9 +210,12 @@ static int tps65217_charger_probe(struct
 	charger->tps = tps;
 	charger->dev = &pdev->dev;
 
+	cfg.of_node = pdev->dev.of_node;
+	cfg.drv_data = charger;
+
 	charger->ac = devm_power_supply_register(&pdev->dev,
 						 &tps65217_charger_desc,
-						 NULL);
+						 &cfg);
 	if (IS_ERR(charger->ac)) {
 		dev_err(&pdev->dev, "failed: power supply register\n");
 		return PTR_ERR(charger->ac);