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Message-ID: <a781481a0705160459p2d538d7fu8096bd594d6df2f9@mail.gmail.com>
Date: Wed, 16 May 2007 17:29:34 +0530
From: "Satyam Sharma" <satyam.sharma@...il.com>
To: "Marcel Holtmann" <marcel@...tmann.org>
Cc: "Jiri Kosina" <jikos@...os.cz>, "Greg KH" <gregkh@...e.de>,
"Jeremy Fitzhardinge" <jeremy@...p.org>, maxk@...lcomm.com,
bluez-devel@...ts.sourceforge.net,
"Cedric Le Goater" <clg@...ibm.com>,
"Linux Kernel Mailing List" <linux-kernel@...r.kernel.org>,
netdev@...r.kernel.org
Subject: Re: 2.6.21-rc7: BUG: sleeping function called from invalid context at net/core/sock.c:1523
On 5/16/07, Satyam Sharma <satyam.sharma@...il.com> 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 <ssatyam@....iitk.ac.in>
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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