From: Guenter Roeck linux@roeck-us.net
commit 1b5f517cca36292076d9e38fa6e33a257703e62e upstream.
If an attempt is made to a sensor with a thermal zone and it fails, the call to devm_thermal_zone_of_sensor_register() may return -ENODEV. This may result in crashes similar to the following.
Unable to handle kernel NULL pointer dereference at virtual address 00000000000003cd ... Internal error: Oops: 96000021 [#1] PREEMPT SMP ... pstate: 60400009 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : mutex_lock+0x18/0x60 lr : thermal_zone_device_update+0x40/0x2e0 sp : ffff800014c4fc60 x29: ffff800014c4fc60 x28: ffff365ee3f6e000 x27: ffffdde218426790 x26: ffff365ee3f6e000 x25: 0000000000000000 x24: ffff365ee3f6e000 x23: ffffdde218426870 x22: ffff365ee3f6e000 x21: 00000000000003cd x20: ffff365ee8bf3308 x19: ffffffffffffffed x18: 0000000000000000 x17: ffffdde21842689c x16: ffffdde1cb7a0b7c x15: 0000000000000040 x14: ffffdde21a4889a0 x13: 0000000000000228 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000001120000 x7 : 0000000000000001 x6 : 0000000000000000 x5 : 0068000878e20f07 x4 : 0000000000000000 x3 : 00000000000003cd x2 : ffff365ee3f6e000 x1 : 0000000000000000 x0 : 00000000000003cd Call trace: mutex_lock+0x18/0x60 hwmon_notify_event+0xfc/0x110 0xffffdde1cb7a0a90 0xffffdde1cb7a0b7c irq_thread_fn+0x2c/0xa0 irq_thread+0x134/0x240 kthread+0x178/0x190 ret_from_fork+0x10/0x20 Code: d503201f d503201f d2800001 aa0103e4 (c8e47c02)
Jon Hunter reports that the exact call sequence is:
hwmon_notify_event() --> hwmon_thermal_notify() --> thermal_zone_device_update() --> update_temperature() --> mutex_lock()
The hwmon core needs to handle all errors returned from calls to devm_thermal_zone_of_sensor_register(). If the call fails with -ENODEV, report that the sensor was not attached to a thermal zone but continue to register the hwmon device.
Reported-by: Jon Hunter jonathanh@nvidia.com Cc: Dmitry Osipenko digetx@gmail.com Fixes: 1597b374af222 ("hwmon: Add notification support") Reviewed-by: Dmitry Osipenko dmitry.osipenko@collabora.com Tested-by: Jon Hunter jonathanh@nvidia.com Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/hwmon/hwmon.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)
--- a/drivers/hwmon/hwmon.c +++ b/drivers/hwmon/hwmon.c @@ -178,12 +178,14 @@ static int hwmon_thermal_add_sensor(stru
tzd = devm_thermal_zone_of_sensor_register(dev, index, tdata, &hwmon_thermal_ops); - /* - * If CONFIG_THERMAL_OF is disabled, this returns -ENODEV, - * so ignore that error but forward any other error. - */ - if (IS_ERR(tzd) && (PTR_ERR(tzd) != -ENODEV)) - return PTR_ERR(tzd); + if (IS_ERR(tzd)) { + if (PTR_ERR(tzd) != -ENODEV) + return PTR_ERR(tzd); + dev_info(dev, "temp%d_input not attached to any thermal zone\n", + index + 1); + devm_kfree(dev, tdata); + return 0; + }
err = devm_add_action(dev, hwmon_thermal_remove_sensor, &tdata->node); if (err)