Messages in this thread | | | From | Jeff Moyer <> | Date | Wed, 28 Apr 2004 10:07:17 -0400 | Subject | Re: netconsole hangs w/ alt-sysrq-t |
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==> Regarding Re: netconsole hangs w/ alt-sysrq-t; Matt Mackall <mpm@selenic.com> adds:
mpm> On Wed, Apr 28, 2004 at 08:44:47AM -0400, Jeff Moyer wrote: >> ==> Regarding Re: netconsole hangs w/ alt-sysrq-t; Matt Mackall >> <mpm@selenic.com> adds: >> mpm> On Thu, Apr 22, 2004 at 11:29:33AM -0400, Jeff Moyer wrote: >> >> If netconsole is enabled, and you hit Alt-Sysrq-t, then it will print >> a >> small amount of output to the console(s) and then hang the system. >> In >> this case, I'm using the e100 driver, and we end up exhausting the >> >> available cbs. Since we are in interrupt context, the driver's poll >> >> routine is never run, and we loop infinitely waiting for resources to >> >> free up that never will. Kernel version is 2.6.5. >> mpm> Can you try 2.6.6-rc2? It has a fix to congestion handling that should mpm> address this. >> Is the attached patch the change you are referring to? If so, I don't >> see how this would fix the problem. I ended up deferring netpoll writes >> to process context, which has been working fine for me. Have I missed >> something?
mpm> Well process context defeats the purpose. Ok, I've more closely read mpm> your report and if I understand correctly, you're using the NAPI mpm> version of e100? There's some magic NAPI bits in netpoll_poll that mpm> might help here:
Yes, sorry I didn't specify that earlier.
mpm> if(trapped && np->dev->poll && test_bit(__LINK_STATE_RX_SCHED, mpm> &np->dev->state)) np-> dev->poll(np->dev, &budget);
mpm> Perhaps we need to pull the trapped test out of there. Then with any mpm> luck, dev->hard_start_xmit will return non-zero in netpoll_send_skb, mpm> we'll call netpoll_poll to pump the card, and we'll be able to flush mpm> it.
I don't think so. You can end up in code running in interrupt context that is not designed to (ip routing code, etc). I've been down that path already. I only defer to process context if irqs_disabled().
Other suggestions?
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