Re: 2.6.21-rc7: BUG: sleeping function called from invalid context at net/core/sock.c:1523

[Herbert Xu]

Jiri Kosina <jikos@xxxxxxxx> wrote:
> 
> Hmm, *sigh*. I guess the patch below fixes the problem, but it is a 
> masterpiece in the field of ugliness. And I am not sure whether it is 
> completely correct either. Are there any immediate ideas for better 
> solution with respect to how struct sock locking works?

Please cc such patches to netdev.  Thanks.

> diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
> index 71f5cfb..c5c93cd 100644
> --- a/net/bluetooth/hci_sock.c
> +++ b/net/bluetooth/hci_sock.c
> @@ -656,7 +656,10 @@ static int hci_sock_dev_event(struct notifier_block *this, unsigned long event,
>                /* Detach sockets from device */
>                read_lock(&hci_sk_list.lock);
>                sk_for_each(sk, node, &hci_sk_list.head) {
> -                       lock_sock(sk);
> +                       if (in_atomic())
> +                               bh_lock_sock(sk);
> +                       else
> +                               lock_sock(sk);

This doesn't do what you think it does.  bh_lock_sock can still succeed
even with lock_sock held by someone else.

Does this need to occur immediately when an event occurs? If not I'd
suggest moving this into a workqueue.

Cheers,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@xxxxxxxxxxxxxxxxxxx>
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