Bluetooth: virtio_bt: Use skb_put to set length

By using skb_put we ensure that skb->tail is set
correctly. Currently, skb->tail is always zero, which
leads to errors, such as the following page fault in
rfcomm_recv_frame:

    BUG: unable to handle page fault for address: ffffed1021de29ff
    #PF: supervisor read access in kernel mode
    #PF: error_code(0x0000) - not-present page
    RIP: 0010:rfcomm_run+0x831/0x4040 (net/bluetooth/rfcomm/core.c:1751)

Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
---
 drivers/bluetooth/virtio_bt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

This is automated email and please do not reply to this email!

Dear submitter,

Thank you for submitting the patches to the linux bluetooth mailing list.
This is a CI test results with your patch series:
PW Link:https://patchwork.kernel.org/project/bluetooth/list/?series=650254

---Test result---

Test Summary:
CheckPatch                    PASS      1.11 seconds
GitLint                       PASS      0.73 seconds
SubjectPrefix                 PASS      0.61 seconds
BuildKernel                   PASS      33.59 seconds
BuildKernel32                 PASS      29.90 seconds
Incremental Build with patchesPASS      38.97 seconds
TestRunner: Setup             PASS      537.03 seconds
TestRunner: l2cap-tester      PASS      14.48 seconds
TestRunner: bnep-tester       PASS      4.49 seconds
TestRunner: mgmt-tester       PASS      85.82 seconds
TestRunner: rfcomm-tester     PASS      7.70 seconds
TestRunner: sco-tester        PASS      7.47 seconds
TestRunner: smp-tester        PASS      7.50 seconds
TestRunner: userchan-tester   PASS      4.69 seconds



---
Regards,
Linux Bluetooth

On 14.06.22 16:52, Soenke Huster wrote:
> By using skb_put we ensure that skb->tail is set
> correctly. Currently, skb->tail is always zero, which
> leads to errors, such as the following page fault in
> rfcomm_recv_frame:
> 
>     BUG: unable to handle page fault for address: ffffed1021de29ff
>     #PF: supervisor read access in kernel mode
>     #PF: error_code(0x0000) - not-present page
>     RIP: 0010:rfcomm_run+0x831/0x4040 (net/bluetooth/rfcomm/core.c:1751)
> 
> Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
> ---
>  drivers/bluetooth/virtio_bt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/bluetooth/virtio_bt.c b/drivers/bluetooth/virtio_bt.c
> index 67c21263f9e0..fd281d439505 100644
> --- a/drivers/bluetooth/virtio_bt.c
> +++ b/drivers/bluetooth/virtio_bt.c
> @@ -219,7 +219,7 @@ static void virtbt_rx_work(struct work_struct *work)
>  	if (!skb)
>  		return;
>  
> -	skb->len = len;
> +	skb_put(skb, len);
>  	virtbt_rx_handle(vbt, skb);
>  
>  	if (virtbt_add_inbuf(vbt) < 0)

Are there any issues with it, or is there another reason why it is not merged yet?

Hi Sönke,

On Fri, Jul 22, 2022 at 4:59 AM Sönke Huster <soenke.huster@eknoes.de> wrote:
>
> On 14.06.22 16:52, Soenke Huster wrote:
> > By using skb_put we ensure that skb->tail is set
> > correctly. Currently, skb->tail is always zero, which
> > leads to errors, such as the following page fault in
> > rfcomm_recv_frame:
> >
> >     BUG: unable to handle page fault for address: ffffed1021de29ff
> >     #PF: supervisor read access in kernel mode
> >     #PF: error_code(0x0000) - not-present page
> >     RIP: 0010:rfcomm_run+0x831/0x4040 (net/bluetooth/rfcomm/core.c:1751)
> >
> > Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
> > ---
> >  drivers/bluetooth/virtio_bt.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/bluetooth/virtio_bt.c b/drivers/bluetooth/virtio_bt.c
> > index 67c21263f9e0..fd281d439505 100644
> > --- a/drivers/bluetooth/virtio_bt.c
> > +++ b/drivers/bluetooth/virtio_bt.c
> > @@ -219,7 +219,7 @@ static void virtbt_rx_work(struct work_struct *work)
> >       if (!skb)
> >               return;
> >
> > -     skb->len = len;
> > +     skb_put(skb, len);
> >       virtbt_rx_handle(vbt, skb);
> >
> >       if (virtbt_add_inbuf(vbt) < 0)
>
> Are there any issues with it, or is there another reason why it is not merged yet?

It appears it was removed from PW due to 30 days inactivity, when that
happens you should resend the patch since it needs to be retested by
CI.