It was found that unloading 'hid_hyperv' module results in a devres
complaint:
...
hv_vmbus: unregistering driver hid_hyperv
------------[ cut here ]------------
WARNING: CPU: 2 PID: 3983 at drivers/base/devres.c:691 devres_release_group+0x1f2/0x2c0
...
Call Trace:
<TASK>
? devres_release_group+0x1f2/0x2c0
? __warn+0xd1/0x1c0
? devres_release_group+0x1f2/0x2c0
? report_bug+0x32a/0x3c0
? handle_bug+0x53/0xa0
? exc_invalid_op+0x18/0x50
? asm_exc_invalid_op+0x1a/0x20
? devres_release_group+0x1f2/0x2c0
? devres_release_group+0x90/0x2c0
? rcu_is_watching+0x15/0xb0
? __pfx_devres_release_group+0x10/0x10
hid_device_remove+0xf5/0x220
device_release_driver_internal+0x371/0x540
? klist_put+0xf3/0x170
bus_remove_device+0x1f1/0x3f0
device_del+0x33f/0x8c0
? __pfx_device_del+0x10/0x10
? cleanup_srcu_struct+0x337/0x500
hid_destroy_device+0xc8/0x130
mousevsc_remove+0xd2/0x1d0 [hid_hyperv]
device_release_driver_internal+0x371/0x540
driver_detach+0xc5/0x180
bus_remove_driver+0x11e/0x2a0
? __mutex_unlock_slowpath+0x160/0x5e0
vmbus_driver_unregister+0x62/0x2b0 [hv_vmbus]
...
And the issue seems to be that the corresponding devres group is not
allocated. Normally, devres_open_group() is called from
__hid_device_probe() but Hyper-V HID driver overrides 'hid_dev->driver'
with 'mousevsc_hid_driver' stub and basically re-implements
__hid_device_probe() by calling hid_parse() and hid_hw_start() but not
devres_open_group(). hid_device_probe() does not call __hid_device_probe()
for it. Later, when the driver is removed, hid_device_remove() calls
devres_release_group() as it doesn't check whether hdev->driver was
initially overridden or not.
The issue seems to be related to the commit 62c68e7cee33 ("HID: ensure
timely release of driver-allocated resources") but the commit itself seems
to be correct.
Fix the issue by dropping the 'hid_dev->driver' override and the
now unneeded hid_parse()/hid_hw_start() calls. One notable difference of
the change is hid_hw_start() is now called with HID_CONNECT_DEFAULT which
implies HID_CONNECT_HIDRAW. This doesn't seem to cause any immediate issues
but 'HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV' combo was used in the
driver for a long time and it is unclear whether hidraw was excluded on
purpose or not.
Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
drivers/hid/hid-hyperv.c | 17 -----------------
1 file changed, 17 deletions(-)
diff --git a/drivers/hid/hid-hyperv.c b/drivers/hid/hid-hyperv.c
index f33485d83d24..1609a56ffa7c 100644
--- a/drivers/hid/hid-hyperv.c
+++ b/drivers/hid/hid-hyperv.c
@@ -431,8 +431,6 @@ static const struct hid_ll_driver mousevsc_ll_driver = {
.raw_request = mousevsc_hid_raw_request,
};
-static struct hid_driver mousevsc_hid_driver;
-
static int mousevsc_probe(struct hv_device *device,
const struct hv_vmbus_device_id *dev_id)
{
@@ -473,7 +471,6 @@ static int mousevsc_probe(struct hv_device *device,
}
hid_dev->ll_driver = &mousevsc_ll_driver;
- hid_dev->driver = &mousevsc_hid_driver;
hid_dev->bus = BUS_VIRTUAL;
hid_dev->vendor = input_dev->hid_dev_info.vendor;
hid_dev->product = input_dev->hid_dev_info.product;
@@ -488,20 +485,6 @@ static int mousevsc_probe(struct hv_device *device,
if (ret)
goto probe_err2;
-
- ret = hid_parse(hid_dev);
- if (ret) {
- hid_err(hid_dev, "parse failed\n");
- goto probe_err2;
- }
-
- ret = hid_hw_start(hid_dev, HID_CONNECT_HIDINPUT | HID_CONNECT_HIDDEV);
-
- if (ret) {
- hid_err(hid_dev, "hw start failed\n");
- goto probe_err2;
- }
-
device_init_wakeup(&device->device, true);
input_dev->connected = true;
--
2.47.0
