On 5/16/07, Satyam Sharma <[EMAIL PROTECTED]> wrote:
Hi Marcel,
[...]
> > > > (later)
> > > > I Googled a bit to see if this problem was faced elsewhere in the kernel
> > > > too. Saw the following commit by Ingo Molnar
> > > > (9883a13c72dbf8c518814b6091019643cdb34429):
> > > > -     lock_sock(sock->sk);
> > > > +     local_bh_disable();
> > > > +     bh_lock_sock_nested(sock->sk);
> > > >       rc = selinux_netlbl_socket_setsid(sock, sksec->sid);
> > > > -     release_sock(sock->sk);
> > > > +     bh_unlock_sock(sock->sk);
> > > > +     local_bh_enable();
> > > > Is it _really_ *this* simple?
> > > [...]
> > > actually this *seems* to be proper solution also for our case, thanks for
> > > pointing this out. I will think about it once again, do some more tests
> > > with this locking scheme, and will let you know.
> >
> > Yes, I can almost confirm that this (open-coding of spin_lock_bh,
> > effectively) is the proper solution (Rusty's unreliable guide to
> > kernel-locking needs to be next to every developer's keyboard :-)
> > I also came across this idiom in other places in the networking code
> > so it seems to be pretty much the standard way. I wish I owned
> > bluetooth hardware, could've tested this for you myself.
>
> does this mean we should revert previous changes to the locking or only
> apply this on top of it?

I've fixed a simple patch on top of 2.6.22-rc1 below.

Eek, please ignore previous one. This one's correct.

Signed-off-by: Satyam Sharma <[EMAIL PROTECTED]>

diff -ruNp a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
--- a/net/bluetooth/hci_sock.c  2007-05-16 17:31:06.000000000 +0530
+++ b/net/bluetooth/hci_sock.c  2007-05-16 17:38:35.000000000 +0530
@@ -665,7 +665,8 @@ static int hci_sock_dev_event(struct not
                /* Detach sockets from device */
                read_lock(&hci_sk_list.lock);
                sk_for_each(sk, node, &hci_sk_list.head) {
-                       lock_sock(sk);
+                       local_bh_disable();
+                       bh_lock_sock_nested(sk);
                        if (hci_pi(sk)->hdev == hdev) {
                                hci_pi(sk)->hdev = NULL;
                                sk->sk_err = EPIPE;
@@ -674,7 +675,8 @@ static int hci_sock_dev_event(struct not

                                hci_dev_put(hdev);
                        }
-                       release_sock(sk);
+                       bh_unlock_sock(sk);
+                       local_bh_enable();
                }
                read_unlock(&hci_sk_list.lock);
        }
-
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