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.
that is any better?
thanks,
greg k-h
