On Fri, Nov 23, 2007 at 01:55:19PM +0300, Evgeniy Polyakov wrote: > On Fri, Nov 23, 2007 at 12:21:57AM -0800, Andrew Morton ([EMAIL PROTECTED]) > wrote: > > > [2059664.615816] __iptables__: init4 IN=ppp0 OUT=ppp0 WARNING: at > > > kernel/softirq.c:139 local_bh_enable() > > > [2059664.620535] [<80120364>] local_bh_enable+0x3c/0x97 > > > > [2059664.620657] [<8011c205>] __call_console_drivers+0x61/0x6d > > > [2059664.620669] [<8011c3fc>] release_console_sem+0x164/0x1bf > > > [2059664.620679] [<8011c81f>] vprintk+0x27a/0x2ff > > > If that trace is to be beieved we're doing nefilter stuff on packets which > > were sent across netconsole. > > > > This probably isn't anything the netfilter guys have thought about. And > > probably we don't want them to. Is there some simple way in which we can > > exempt netconsole from netfilter processing? > > This is not about netfilter, but about freeing skb in interrupt context, > which is not allowed, and in interrupt skbs are queued to be freed in softirq, > but netcnsole wants to flush softirq freeing queue. That is a question: why?
My memory here is hazy, but I think this exists to rescue netconsole in low-memory situations. This bit originated with Ingo, so maybe he can recall. Netpoll can process an arbitrary number of skbs inside a single interrupt. Think sysrq-t at one packet per line or kgdboe where the entire trace session can happen inside one very long interrupt. Perhaps we can refine this to mark netpoll's skbs (perhaps with ->destructor?) and delete only skbs we own. As these are never passed through any of the other route/xfrm/filter code, they should be safe to delete even in irq context, yes? > Removing zap_completion_queue() from find_skb() will fix the warning, > but I'm not sure this is a correct fix. I've added Matt to the Cc list. Care to try the sysrq-t or OOM message tests? -- Mathematics is the supreme nostalgia of our time. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
