[PATCH AUTOSEL 5.15 23/68] HID: ft260: fix i2c probing for hwmon devices

Sasha Levin
2021-11-30T14:50:19Z

From: Michael Zaidman <michael.zaidman@gmail.com>

[ Upstream commit a94f61e63f337d95001e1a976ab701100fa1d666 ]

The below scenario causes the kernel NULL pointer dereference failure:
1. sudo insmod hid-ft260.ko
2. sudo modprobe lm75
3. unplug USB hid-ft260
4. plug USB hid-ft260

[ +0.000006] Call Trace:
[ +0.000004] __i2c_smbus_xfer.part.0+0xd1/0x310
[ +0.000007] ? ft260_smbus_write+0x140/0x140 [hid_ft260]
[ +0.000005] __i2c_smbus_xfer+0x2b/0x80
[ +0.000004] i2c_smbus_xfer+0x61/0xf0
[ +0.000005] i2c_default_probe+0xf9/0x130
[ +0.000004] i2c_detect_address+0x84/0x160
[ +0.000004] ? kmem_cache_alloc_trace+0xf6/0x200
[ +0.000009] ? i2c_detect.isra.0+0x69/0x130
[ +0.000005] i2c_detect.isra.0+0xbf/0x130
[ +0.000004] ? __process_new_driver+0x30/0x30
[ +0.000004] __process_new_adapter+0x18/0x20
[ +0.000004] bus_for_each_drv+0x84/0xd0
[ +0.000003] i2c_register_adapter+0x1e4/0x400
[ +0.000005] i2c_add_adapter+0x5c/0x80
[ +0.000004] ft260_probe.cold+0x222/0x2e2 [hid_ft260]
[ +0.000006] hid_device_probe+0x10e/0x170 [hid]
[ +0.000009] really_probe+0xff/0x460
[ +0.000004] driver_probe_device+0xe9/0x160
[ +0.000003] __device_attach_driver+0x71/0xd0
[ +0.000004] ? driver_allows_async_probing+0x50/0x50
[ +0.000004] bus_for_each_drv+0x84/0xd0
[ +0.000002] __device_attach+0xde/0x1e0
[ +0.000004] device_initial_probe+0x13/0x20
[ +0.000004] bus_probe_device+0x8f/0xa0
[ +0.000003] device_add+0x333/0x5f0

It happened when i2c core probed for the devices associated with the lm75
driver by invoking 2c_detect()-->..-->ft260_smbus_write() from within the
ft260_probe before setting the adapter data with i2c_set_adapdata().

Moving the i2c_set_adapdata() before i2c_add_adapter() fixed the failure.

Signed-off-by: Michael Zaidman <michael.zaidman@gmail.com>
Signed-off-by: Germain Hebert <germain.hebert@ca.abb.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hid/hid-ft260.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/drivers/hid/hid-ft260.c b/drivers/hid/hid-ft260.c
index 4ef1c3b8094ea..8ee77f4afe9ff 100644
--- a/drivers/hid/hid-ft260.c
+++ b/drivers/hid/hid-ft260.c
@@ -966,24 +966,23 @@ static int ft260_probe(struct hid_device *hdev, const struct hid_device_id *id)
mutex_init(&dev->lock);
init_completion(&dev->wait);

+ ret = ft260_xfer_status(dev);
+ if (ret)
+ ft260_i2c_reset(hdev);
+
+ i2c_set_adapdata(&dev->adap, dev);
ret = i2c_add_adapter(&dev->adap);
if (ret) {
hid_err(hdev, "failed to add i2c adapter\n");
goto err_hid_close;
}

- i2c_set_adapdata(&dev->adap, dev);
-
ret = sysfs_create_group(&hdev->dev.kobj, &ft260_attr_group);
if (ret < 0) {
hid_err(hdev, "failed to create sysfs attrs\n");
goto err_i2c_free;
}

- ret = ft260_xfer_status(dev);
- if (ret)
- ft260_i2c_reset(hdev);
-
return 0;

err_i2c_free:
--
2.33.0