Hi Enric, On Tue, Nov 27, 2018 at 4:19 AM Enric Balletbo i Serra <enric.balle...@collabora.com> wrote: > > Devices are required to provide a release method. This patch fixes the > following WARN(): > > [ 47.218707] ------------[ cut here ]------------ > [ 47.223901] Device 'cros_ec' does not have a release() function, it is > broken and must be fixed. > [ 47.234430] WARNING: CPU: 0 PID: 3585 at drivers/base/core.c:895 > device_release+0x80/0x90 > [ 47.243560] Modules linked in: btusb btrtl btintel btbcm bluetooth > ecdh_generic [...] > [ 47.323851] CPU: 0 PID: 3585 Comm: rmmod Not tainted 4.20.0-rc2+ #29 > [ 47.330947] Hardware name: Google Kevin (DT) > [ 47.335714] pstate: 40000005 (nZcv daif -PAN -UAO) > [ 47.341063] pc : device_release+0x80/0x90 > [ 47.345537] lr : device_release+0x80/0x90 > [ 47.350001] sp : ffff00000b17bc70 > [ 47.353698] x29: ffff00000b17bc70 x28: ffff8000e48e9a80 > [ 47.359629] x27: 0000000000000000 x26: 0000000000000000 > [ 47.365561] x25: 0000000056000000 x24: 0000000000000015 > [ 47.371492] x23: ffff8000f0248060 x22: ffff000000b700a0 > [ 47.377414] x21: ffff8000edf56100 x20: ffff8000edd13028 > [ 47.383346] x19: ffff8000edd13018 x18: 0000000000000095 > [ 47.389278] x17: 0000000000000000 x16: 0000000000000000 > [ 47.395209] x15: 0000000000000400 x14: 0000000000000400 > [ 47.401131] x13: 00000000000001a7 x12: 0000000000000000 > [ 47.407053] x11: 0000000000000001 x10: 0000000000000960 > [ 47.412976] x9 : ffff00000b17b9b0 x8 : ffff8000e48ea440 > [ 47.418898] x7 : ffff8000ee9090c0 x6 : ffff8000f7d0b0b8 > [ 47.424830] x5 : ffff8000f7d0b0b8 x4 : 0000000000000000 > [ 47.430752] x3 : ffff8000f7d11e68 x2 : ffff8000e48e9a80 > [ 47.436674] x1 : 37d859939c964800 x0 : 0000000000000000 > [ 47.442597] Call trace: > [ 47.445324] device_release+0x80/0x90 > [ 47.449414] kobject_put+0x74/0xe8 > [ 47.453210] device_unregister+0x20/0x30 > [ 47.457592] ec_device_remove+0x34/0x48 [cros_ec_dev] > [ 47.463233] platform_drv_remove+0x28/0x48 > [ 47.467805] device_release_driver_internal+0x1a8/0x240 > [ 47.473630] driver_detach+0x40/0x80 > [ 47.477609] bus_remove_driver+0x54/0xa8 > [ 47.481986] driver_unregister+0x2c/0x58 > [ 47.486355] platform_driver_unregister+0x10/0x18 > [ 47.491599] cros_ec_dev_exit+0x1c/0x258 [cros_ec_dev] > [ 47.497338] __arm64_sys_delete_module+0x16c/0x1f8 > [ 47.502689] el0_svc_common+0x84/0xd8 > [ 47.506776] el0_svc_handler+0x2c/0x80 > [ 47.510960] el0_svc+0x8/0xc > [ 47.514171] ---[ end trace 9087279fc8c03450 ]--- > > Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com> > --- > > Changes in v3: None > Changes in v2: > - Fix WARN when unloading. This is new in these series. > > drivers/mfd/cros_ec_dev.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c > index 1ba98a32715e..cdb941c6db98 100644 > --- a/drivers/mfd/cros_ec_dev.c > +++ b/drivers/mfd/cros_ec_dev.c > @@ -35,9 +35,14 @@ > #define CROS_MAX_DEV 128 > static int ec_major; > > +static void cros_ec_dev_release(struct device *dev) > +{ > +} > +
This tends to be a wrong solution. Problem is that object lifetime is not necessarily tied to device lifetime. Greg KH (copied) has a much better understanding of the problem than I do. Guenter > static struct class cros_class = { > .owner = THIS_MODULE, > .name = "chromeos", > + .dev_release = cros_ec_dev_release, > }; > > /* Basic communication */ > -- > 2.19.1 >