On Mon, Aug 22, 2022 at 10:44:26AM +0800, Linyu Yuan wrote: > > On 8/21/2022 2:40 AM, Greg Kroah-Hartman wrote: > > On Fri, Aug 19, 2022 at 06:32:43PM +0200, Takashi Iwai wrote: > > > Hi, > > > > > > we've got multiple reports about 5.19 kernel starting crashing after > > > some time, and this turned out to be triggered by ucsi_acpi driver. > > > The details are found in: > > > https://bugzilla.suse.com/show_bug.cgi?id=1202386 > > > > > > The culprit seems to be the commit 87d0e2f41b8c > > > usb: typec: ucsi: add a common function ucsi_unregister_connectors() > > Adding Heikki to the thread... > > > > > This commit looks as if it were a harmless cleanup, but this failed in > > > a subtle way. Namely, in the error scenario, the driver gets an error > > > at ucsi_register_altmodes(), and goes to the error handling to release > > > the resources. Through this refactoring, the release part was unified > > > to a funciton ucsi_unregister_connectors(). And there, it has a NULL > > > check of con->wq, and it bails out the loop if it's NULL. > > > Meanwhile, ucsi_register_port() itself still calls destroy_workqueue() > > > and clear con->wq at its error path. This ended up in the leftover > > > power supply device with the uninitialized / cleared device. > > > > > > It was confirmed that the problem could be avoided by a simple > > > revert. > > I'll be glad to revert this now, unless Heikki thinks: > > > > > I guess another fix could be removing the part clearing con->wq, i.e. > > > > > > --- a/drivers/usb/typec/ucsi/ucsi.c > > > +++ b/drivers/usb/typec/ucsi/ucsi.c > > > @@ -1192,11 +1192,6 @@ static int ucsi_register_port(struct ucsi *ucsi, int index) > > > out_unlock: > > > mutex_unlock(&con->lock); > > > - if (ret && con->wq) { > > > - destroy_workqueue(con->wq); > > > - con->wq = NULL; > > > - } > > > - > > > return ret; > > > } > > > > > > ... but it's totally untested and I'm not entirely sure whether it's > > > better. > > this part is original code, yes, but when I make the change you mentioned, > > as in the function ucsi_unregister_connectors(), just use con->wq to > represent which connector initialized previous, > > indeed if we clear it in ucsi_register_port(), something will left unclear. > > please send a patch to fix it. > > I think your change is good. Ok, can someone send me a patch to apply to the tree for this? thanks, greg k-h
