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

From: Satyam Sharma
Date: Wed May 16 2007 - 07:36:59 EST


Hi Jiri,

On 5/16/07, Jiri Kosina <jikos@xxxxxxxx> wrote:
On Fri, 11 May 2007, Satyam Sharma wrote:
> (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.

Thanks,
Satyam
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