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)

Fixes: afd2daa26c7a ("Bluetooth: Add support for virtio transport driver")
Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
---
v2: Add Fixes tag
 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)
-- 
2.36.1

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)

Fixes: afd2daa26c7a ("Bluetooth: Add support for virtio transport driver")
Signed-off-by: Soenke Huster <soenke.huster@eknoes.de>
---
v2: Add Fixes tag
 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)
-- 
2.36.1

Hello:

This patch was applied to bluetooth/bluetooth-next.git (master)
by Luiz Augusto von Dentz <luiz.von.dentz@intel.com>:

On Wed, 12 Oct 2022 09:45:06 +0200 you 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)
> 
> [...]

Here is the summary with links:
  - [v2,RESEND] Bluetooth: virtio_bt: Use skb_put to set length
    https://git.kernel.org/bluetooth/bluetooth-next/c/6ab8872f1976

You are awesome, thank you!
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