Re: [PATCH] Bluetooth-next: Add incremental indexing in sysfs HCI connection name.

[Marcel Holtmann <marcel@holtmann.org>]

Hi Doron,

> The patch fixes kernel panic which is due to race condition
> between the setup of incomming connection and clean-up of the
> dead one. Observed in the following case: attached HID device
> disconnects unexpectedly (without performing ACL disconnect ),
> the device tries to connect again before the ACL link time-out
> fires, this translates to the HCI_DISCONNECT, HCI_CONNECT_REQ
> events on the same handle, since HCI_DISCONNECT trigers the clean
> up of the HID device and handled in different context, the
> linking/unlinking connection object to sysfs, may mess up.
> 
> Signed-off-by: Ilia Kolominsky <iliak@ti.com>
> ---
>  net/bluetooth/hci_sysfs.c |    4 +++-
>  1 files changed, 3 insertions(+), 1 deletions(-)
> 
> diff --git a/net/bluetooth/hci_sysfs.c b/net/bluetooth/hci_sysfs.c
> index a6c3aa8..5967d63 100644
> --- a/net/bluetooth/hci_sysfs.c
> +++ b/net/bluetooth/hci_sysfs.c
> @@ -9,6 +9,7 @@
>  #include <net/bluetooth/bluetooth.h>
>  #include <net/bluetooth/hci_core.h>
>  
> +static int acl_conn_index = 0;
>  static struct class *bt_class;
>  
>  struct dentry *bt_debugfs;
> @@ -91,7 +92,8 @@ static void add_conn(struct work_struct *work)
>  	struct hci_conn *conn = container_of(work, struct hci_conn, work_add);
>  	struct hci_dev *hdev = conn->hdev;
>  
> -	dev_set_name(&conn->dev, "%s:%d", hdev->name, conn->handle);
> +	acl_conn_index++;
> +	dev_set_name(&conn->dev, "%s:%d:%d", hdev->name, conn->handle, acl_conn_index);
>  
>  	dev_set_drvdata(&conn->dev, conn);

can we get a bit more of details on what this is actually trying to
solve. I do not like this way of solving it at all. I think it is trying
to cover up symptoms and not fixing the real issue.

Regards

Marcel