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Message-ID: <97d5cdb9-0372-7e8b-dc61-610198f8664f@applied-asynchrony.com>
Date: Mon, 30 Aug 2021 21:23:22 +0200
From: Holger Hoffstätte <holger@...lied-asynchrony.com>
To: Michal Kubecek <mkubecek@...e.cz>,
Alan Stern <stern@...land.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-usb@...r.kernel.org, linux-input@...r.kernel.org,
linux-kernel@...r.kernel.org, Jiri Kosina <jikos@...nel.org>,
Benjamin Tissoires <benjamin.tissoires@...hat.com>
Subject: Re: [REGRESSION][BISECTED] flood of "hid-generic ... control queue
full" since v5.14-rc1
On 2021-08-16 21:12, Michal Kubecek wrote:
> On Mon, Aug 16, 2021 at 10:38:56AM -0400, Alan Stern wrote:
>> On Mon, Aug 16, 2021 at 04:13:47PM +0200, Michal Kubecek wrote:
>>> Looking at the code, the primary problem seems to be that the "else"
>>> branch in hid_submit_ctrl() recalculates transfer_buffer_length to
>>> a rounded up value but assigns the original length to wLength.
>>
>> Looks like you found the bug. Fixing it might be as simple as setting
>> len = padlen in that "else" branch. You could then combine the
>> transfer_buffer_length assignment with the one in the "if" branch and
>> hoist them out after the entire "if" statement.
>
> With the patch below, there are no errors and the UPS communication
> works correctly and so do other HID devices. But I would prefere someone
> familiar with HID code to confirm that this is what we want and what
> would be the right way to handle usb_submit_urb() errors.
>
> Michal
>
> diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
> index 06130dc431a0..ef240ef63a66 100644
> --- a/drivers/hid/usbhid/hid-core.c
> +++ b/drivers/hid/usbhid/hid-core.c
> @@ -377,27 +377,26 @@ static int hid_submit_ctrl(struct hid_device *hid)
> len = hid_report_len(report);
> if (dir == USB_DIR_OUT) {
> usbhid->urbctrl->pipe = usb_sndctrlpipe(hid_to_usb_dev(hid), 0);
> - usbhid->urbctrl->transfer_buffer_length = len;
> if (raw_report) {
> memcpy(usbhid->ctrlbuf, raw_report, len);
> kfree(raw_report);
> usbhid->ctrl[usbhid->ctrltail].raw_report = NULL;
> }
> } else {
> - int maxpacket, padlen;
> + int maxpacket;
>
> usbhid->urbctrl->pipe = usb_rcvctrlpipe(hid_to_usb_dev(hid), 0);
> maxpacket = usb_maxpacket(hid_to_usb_dev(hid),
> usbhid->urbctrl->pipe, 0);
> if (maxpacket > 0) {
> - padlen = DIV_ROUND_UP(len, maxpacket);
> - padlen *= maxpacket;
> - if (padlen > usbhid->bufsize)
> - padlen = usbhid->bufsize;
> + len = DIV_ROUND_UP(len, maxpacket);
> + len *= maxpacket;
> + if (len > usbhid->bufsize)
> + len = usbhid->bufsize;
> } else
> - padlen = 0;
> - usbhid->urbctrl->transfer_buffer_length = padlen;
> + len = 0;
> }
> + usbhid->urbctrl->transfer_buffer_length = len;
> usbhid->urbctrl->dev = hid_to_usb_dev(hid);
>
> usbhid->cr->bRequestType = USB_TYPE_CLASS | USB_RECIP_INTERFACE | dir;
>
Got the same flood of messages when trying 5.14.0, found this thread, applied
the patch & rebuilt, problem is gone & UPS still working fine. Yay.
cheers
Holger
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