On Mon, 18 Mar 2019 08:39:22 -0700 Guenter Roeck <linux@xxxxxxxxxxxx> wrote: > On Mon, Mar 18, 2019 at 03:06:00PM +0000, Marc Zyngier wrote: > > Running a kernel with the fusb302 driver and lockdep enabled > > leads to an unpleasant warning: > > > > [ 4.617477] INFO: trying to register non-static key. > > [ 4.617930] the code is fine but needs lockdep annotation. > > [ 4.618418] turning off the locking correctness validator. > > [ 4.618913] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.1.0-rc1-00007-g3542533f3fc9 #13 > > [ 4.619620] Hardware name: rockchip evb_rk3399/evb_rk3399, BIOS 2019.04-rc3-00124-g2feec69fb1 03/15/2019 > > [ 4.620454] Call trace: > > [ 4.620693] dump_backtrace+0x0/0x138 > > [ 4.621028] show_stack+0x24/0x30 > > [ 4.621336] dump_stack+0xbc/0x104 > > [ 4.621649] register_lock_class+0x594/0x598 > > [ 4.622036] __lock_acquire+0x80/0x11b8 > > [ 4.622384] lock_acquire+0xdc/0x260 > > [ 4.622711] __mutex_lock+0x90/0x8a0 > > [ 4.623037] mutex_lock_nested+0x3c/0x50 > > [ 4.623394] _fusb302_log+0x88/0x1f0 > > [ 4.623721] fusb302_log+0x7c/0xa0 > > [ 4.624033] tcpm_init+0x5c/0x190 > > [ 4.624336] tcpm_init+0x3c/0x130 > > [ 4.624640] tcpm_register_port+0x574/0x878 > > [ 4.625019] fusb302_probe+0x2c8/0x590 > > > > Despite what the message says, the code isn't fine, as it tries to > > make use of the fusb302_log facility pretty early. This requires the > > logbuffer_lock mutex to be initialised, but that only happens much > > later. Boo. > > > > Hoist the fusb302_debugfs_init call before tcpm_register_port so that > > we can enjoy a working mutex. > > > > Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> > > --- > > drivers/usb/typec/tcpm/fusb302.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c > > index e9344997329c..7e3f8901daf6 100644 > > --- a/drivers/usb/typec/tcpm/fusb302.c > > +++ b/drivers/usb/typec/tcpm/fusb302.c > > @@ -1790,6 +1790,7 @@ static int fusb302_probe(struct i2c_client *client, > > goto destroy_workqueue; > > } > > > > + fusb302_debugfs_init(chip); > > This needs another error exit label right after destroy_workqueue, > and an added call to fusb302_debugfs_exit() after that label. You do mean before destroy_workqueue, right? Otherwise, the error handling doesn't nest properly... Something like this: diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c index 7e3f8901daf6..76cb8be6f3eb 100644 --- a/drivers/usb/typec/tcpm/fusb302.c +++ b/drivers/usb/typec/tcpm/fusb302.c @@ -1796,7 +1796,7 @@ static int fusb302_probe(struct i2c_client *client, ret = PTR_ERR(chip->tcpm_port); if (ret != -EPROBE_DEFER) dev_err(dev, "cannot register tcpm port, ret=%d", ret); - goto destroy_workqueue; + goto unregister_debugfs; } ret = devm_request_threaded_irq(chip->dev, chip->gpio_int_n_irq, @@ -1814,6 +1814,8 @@ static int fusb302_probe(struct i2c_client *client, tcpm_unregister_port: tcpm_unregister_port(chip->tcpm_port); +unregister_debugfs: + fusb302_debugfs_exit(chip); destroy_workqueue: destroy_workqueue(chip->wq); Thanks, M. -- Without deviation from the norm, progress is not possible.
