Re: linux-2.6.11-rc3 and isdn mppp

[Herbert Xu]

On Sat, Feb 12, 2005 at 04:50:23PM +0000, Christian Heim wrote:
> Well, i have to setup ISDN here at home, and wanted to use both channels.
> I am able to add the second channel, but then the kernel (at least i think) 
> starts to complain.
> 
> >17:36:22 kraftwerk Badness in local_bh_enable at kernel/softirq.c:140
> >17:36:22 kraftwerk [<c011b201>] local_bh_enable+0x71/0x80
> >17:36:22 kraftwerk [<c030c1a7>] isdn_ppp_xmit+0xe7/0x7d0

isdn_net_get_locked_lp is doing a local_bh_enable with hard IRQs
disabled.  This is not allowed.

The following patch fixes the problem by removing the unnecessary
local_bh_enable while the hard IRQs are disabled.

Signed-off-by: Herbert Xu <[EMAIL PROTECTED]>

Cheers,
-- 
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Email: Herbert Xu ~{PmV>HI~} <[EMAIL PROTECTED]>
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===== drivers/isdn/i4l/isdn_net.h 1.48 vs edited =====
--- 1.48/drivers/isdn/i4l/isdn_net.h    2004-06-23 00:44:03 +10:00
+++ edited/drivers/isdn/i4l/isdn_net.h  2005-02-14 08:52:19 +11:00
@@ -78,18 +78,19 @@
 
        spin_lock_irqsave(&nd->queue_lock, flags);
        lp = nd->queue;         /* get lp on top of queue */
-       spin_lock_bh(&nd->queue->xmit_lock);
+       spin_lock(&nd->queue->xmit_lock);
        while (isdn_net_lp_busy(nd->queue)) {
-               spin_unlock_bh(&nd->queue->xmit_lock);
+               spin_unlock(&nd->queue->xmit_lock);
                nd->queue = nd->queue->next;
                if (nd->queue == lp) { /* not found -- should never happen */
                        lp = NULL;
                        goto errout;
                }
-               spin_lock_bh(&nd->queue->xmit_lock);
+               spin_lock(&nd->queue->xmit_lock);
        }
        lp = nd->queue;
        nd->queue = nd->queue->next;
+       local_bh_disable();
 errout:
        spin_unlock_irqrestore(&nd->queue_lock, flags);
        return lp;