On Mon, Nov 04, 2024 at 05:48:24PM +0100, Vitaly Kuznetsov wrote:
> 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>
A fixme tag would be helpful.
> ---
> 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
>
I have tested this patch, but the original issue reported in commit message is
not observed in latest kernel due to an other error reported by Michael here:
https://lore.kernel.org/linux-hyperv/SN6PR02MB41573CDE3E478455D17837DED4502@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
The error addressed by this patch is observed before the commit
"8b7fd6a15f8c: HID: bpf: move HID-BPF report descriptor fixup earlier",
and is resolved by this patch. In fact, this patch appears to fix both issues.
Tested-by: Saurabh Sengar <ssengar@xxxxxxxxxxxxxxxxxxx>
- Saurabh
