[PATCH 3.10 60/66] power: max17040: Fix NULL pointer dereference when there is no platform_data

Greg Kroah-Hartman
2014-02-21T00:46:06Z

From: Krzysztof Kozlowski <k.kozlowski@samsung.com>

commit ac323d8d807060f7c95a685a9fe861e7b6300993 upstream.

Fix NULL pointer dereference of "chip->pdata" if platform_data was not
supplied to the driver.

The driver during probe stored the pointer to the platform_data:
chip->pdata = client->dev.platform_data;
Later it was dereferenced in max17040_get_online() and
max17040_get_status().

If platform_data was not supplied, the NULL pointer exception would
happen:

[ 6.626094] Unable to handle kernel of a at virtual address 00000000
[ 6.628557] pgd = c0004000
[ 6.632868] [00000000] *pgd=66262564
[ 6.634636] Unable to handle kernel paging request at virtual address e6262000
[ 6.642014] pgd = de468000
[ 6.644700] [e6262000] *pgd=00000000
[ 6.648265] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[ 6.653552] Modules linked in:
[ 6.656598] CPU: 0 PID: 31 Comm: kworker/0:1 Not tainted 3.10.14-02717-gc58b4b4 #505
[ 6.664334] Workqueue: events max17040_work
[ 6.668488] task: dfa11b80 ti: df9f6000 task.ti: df9f6000
[ 6.673873] PC is at show_pte+0x80/0xb8
[ 6.677687] LR is at show_pte+0x3c/0xb8
[ 6.681503] pc : [<c001b7b8>] lr : [<c001b774>] psr: 600f0113
[ 6.681503] sp : df9f7d58 ip : 600f0113 fp : 00000009
[ 6.692965] r10: 00000000 r9 : 00000000 r8 : dfa11b80
[ 6.698171] r7 : df9f7ea0 r6 : e6262000 r5 : 00000000 r4 : 00000000
[ 6.704680] r3 : 00000000 r2 : e6262000 r1 : 600f0193 r0 : c05b3750
[ 6.711194] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
[ 6.718485] Control: 10c53c7d Table: 5e46806a DAC: 00000015
[ 6.724218] Process kworker/0:1 (pid: 31, stack limit = 0xdf9f6238)
[ 6.730465] Stack: (0xdf9f7d58 to 0xdf9f8000)
[ 6.914325] [<c001b7b8>] (show_pte+0x80/0xb8) from [<c047107c>] (__do_kernel_fault.part.9+0x44/0x74)
[ 6.923425] [<c047107c>] (__do_kernel_fault.part.9+0x44/0x74) from [<c001bb7c>] (do_page_fault+0x2c4/0x360)
[ 6.933144] [<c001bb7c>] (do_page_fault+0x2c4/0x360) from [<c0008400>] (do_DataAbort+0x34/0x9c)
[ 6.941825] [<c0008400>] (do_DataAbort+0x34/0x9c) from [<c000e5d8>] (__dabt_svc+0x38/0x60)
[ 6.950058] Exception stack(0xdf9f7ea0 to 0xdf9f7ee8)
[ 6.955099] 7ea0: df0c1790 00000000 00000002 00000000 df0c1794 df0c1790 df0c1790 00000042
[ 6.963271] 7ec0: df0c1794 00000001 00000000 00000009 00000000 df9f7ee8 c0306268 c0306270
[ 6.971419] 7ee0: a00f0113 ffffffff
[ 6.974902] [<c000e5d8>] (__dabt_svc+0x38/0x60) from [<c0306270>] (max17040_work+0x8c/0x144)
[ 6.983317] [<c0306270>] (max17040_work+0x8c/0x144) from [<c003f364>] (process_one_work+0x138/0x440)
[ 6.992429] [<c003f364>] (process_one_work+0x138/0x440) from [<c003fa64>] (worker_thread+0x134/0x3b8)
[ 7.001628] [<c003fa64>] (worker_thread+0x134/0x3b8) from [<c00454bc>] (kthread+0xa4/0xb0)
[ 7.009875] [<c00454bc>] (kthread+0xa4/0xb0) from [<c000eb28>] (ret_from_fork+0x14/0x2c)
[ 7.017943] Code: e1a03005 e2422480 e0826104 e59f002c (e7922104)
[ 7.024017] ---[ end trace 73bc7006b9cc5c79 ]---

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Fixes: c6f4a42de60b981dd210de01cd3e575835e3158e
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/power/max17040_battery.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

--- a/drivers/power/max17040_battery.c
+++ b/drivers/power/max17040_battery.c
@@ -148,7 +148,7 @@ static void max17040_get_online(struct i
{
struct max17040_chip *chip = i2c_get_clientdata(client);

- if (chip->pdata->battery_online)
+ if (chip->pdata && chip->pdata->battery_online)
chip->online = chip->pdata->battery_online();
else
chip->online = 1;
@@ -158,7 +158,8 @@ static void max17040_get_status(struct i
{
struct max17040_chip *chip = i2c_get_clientdata(client);

- if (!chip->pdata->charger_online || !chip->pdata->charger_enable) {
+ if (!chip->pdata || !chip->pdata->charger_online
+ || !chip->pdata->charger_enable) {
chip->status = POWER_SUPPLY_STATUS_UNKNOWN;
return;
}