Re: [v3.11][Regression] HID: hyperv: convert alloc+memcpy to memdup

[David Herrmann]

Hi

On Mon, Dec 16, 2013 at 2:01 PM, Jiri Kosina <jkosina@xxxxxxx> wrote:
> On Fri, 27 Sep 2013, Joseph Salisbury wrote:
>
>> >> commit b1a1442a23776756b254b69786848a94d92445ba
>> >> Author: Jiri Kosina <jkosina@xxxxxxx>
>> >> Date: Mon Jun 3 11:27:48 2013 +0200
>> >>
>> >>     HID: core: fix reporting of raw events
>> >>
>> >> Reverting this commit in v3.12-rc2 prevents the system from locking up,
>> >> which happens when connecting a bluetooth trackpad.
>> >>
>> >> Jiri, do you think we should revert this patch, or is there some further
>> >> debugging/data collecting you would like to do?
>> > Hi Joseph,
>> >
>> > in this mail:
>> >
>> >     Message-ID: <5241992E.3090805@xxxxxxxxxxxxx>
>> >     Date: Tue, 24 Sep 2013 09:52:46 -0400
>> >
>> > you said that reverting this commit doesn't prevent the lockups, so I am
>> > rather confused ... ?
>> >
>> > Thanks,
>> >
>> The testing was invalid.  Reverting commit b1a1442 does resolve the bug
>> and stop the lockups.
>
> Okay, I finally got some sense of this, sorry for the delay.
>
> Could you please test with the patch below, instead of reverting
> b1a1442a23? Thanks a lot.
>
>
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 253fe23..81eacd3 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -1334,7 +1334,7 @@ int hid_report_raw_event(struct hid_device *hid, int type, u8 *data, int size,
>                 csize--;
>         }
>
> -       rsize = ((report->size - 1) >> 3) + 1;
> +       rsize = ((report->size - 1) >> 3) + 1 + (report->id > 0) + 7;

Isn't "report->id" already covered by "if (report_enum->numbered)"
above? The test for "id > 0" won't work here as in this case
"report_enum->numbered" must already be set to true by the hid-desc
parser, doesn't it?

Where exactly did you get the +7 from?

What worries me here is that we write over the @data buffer from the
hid-ll-driver if the report is too short. I don't think the BT driver
accounts for that, mhh.

David

>         if (rsize > HID_MAX_BUFFER_SIZE)
>                 rsize = HID_MAX_BUFFER_SIZE;
>
> --
> Jiri Kosina
> SUSE Labs
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