Messages in this thread | | | Date | Thu, 4 Jan 2001 11:51:59 +0100 | From | Florian Lohoff <> | Subject | Re: [Linux-IrDA]Re: [IrDA+SMP] Lockup in handle_IRQ_event |
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On Thu, Jan 04, 2001 at 10:18:46AM +1100, Andrew Morton wrote: > Marc ZYNGIER wrote: > > > > Hi all, > > > > Having just started playing with IrDA on my dual celeron (Abit "APIC > > error..." BP6), I managed to kill it every single time (NMI watchdog > > in handle_IRQ_event) while connecting to my mobile phone (in fact, > > when closing the connection to the phone. even 'cat /dev/ircomm0' will > > do...). This is perfectly repeatable. > > > > Try this: > > --- linux-2.4.0-prerelease/net/irda/irqueue.c Tue Nov 21 20:11:22 2000 > +++ linux-akpm/net/irda/irqueue.c Thu Jan 4 10:14:10 2001 > @@ -436,7 +436,7 @@ > > /* Release lock */ > if ( hashbin->hb_type & HB_GLOBAL) { > - spin_unlock_irq( &hashbin->hb_mutex[ bin]); > + spin_unlock_irqrestore( &hashbin->hb_mutex[ bin], flags); > > } else if ( hashbin->hb_type & HB_LOCAL) { > restore_flags( flags);
BTW: What i have seen in the ircomm_tty.c (2.2.18):
647 save_flags(flags); 648 cli(); 649 650 skb = self->tx_skb; 651 self->tx_skb = NULL; 652 653 restore_flags(flags);
and a lot of other places simply use "save_flags(flags); cli(); restore_flags()". Can someone enlighten me how this is supposed to work on SMP machines ? AFAIK "cli()" only disables IRQs on the local CPU so a different CPU could easily stumple half way as this is definitly non atomic. Or is the tty layer protected by some "big tty lock" ?
Flo -- Florian Lohoff flo@rfc822.org +49-5201-669912 Why is it called "common sense" when nobody seems to have any?
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