Re: Bad skb and hard irq messages with 2.3.49, PPP, USB modem

From: Michael H. Warfield (mhw@wittsend.com)
Date: Mon Mar 06 2000 - 09:43:39 EST


On Mon, Mar 06, 2000 at 02:56:56PM +0100, Jamie Lokier wrote:
> My log just filled up. Lots and lots of dubious messages about bad skbs
> and hard IRQs. It's a ppp link that worked fine with 2.3.40.

        I just upgraded from 2.3.47 to 2.3.49 and now I'm being flooded
as well with messages like these:

] Mar 6 09:38:47 localhost kernel: ip_local_deliver: bad loopback skb:
] Mar 6 09:38:47 localhost kernel: skb: pf=2 (unowned) dev=lo len=60
] Mar 6 09:38:47 localhost kernel: PROTO=17 127.0.0.1:1031 127.0.0.1:512 L=60 S=0x00 I=0 F=0x4000 T=64
] Mar 6 09:38:47 localhost kernel: ip_finish_output: bad owned skb = c7fa7920:
] Mar 6 09:38:48 localhost kernel: skb: pf=2 (owned) dev=lo len=88
] Mar 6 09:38:48 localhost kernel: PROTO=1 127.0.0.1:0 127.0.0.1:0 L=88 S=0xC0 I=0 F=0x4000 T=255
] Mar 6 09:38:48 localhost kernel: ip_local_deliver: bad loopback skb:
] Mar 6 09:38:48 localhost kernel: skb: pf=2 (unowned) dev=lo len=88
] Mar 6 09:38:48 localhost kernel: PROTO=1 127.0.0.1:0 127.0.0.1:0 L=88 S=0xC0 I=0 F=0x4000 T=255
] Mar 6 09:39:26 localhost kernel: ip_local_deliver: bad non-lo skb:
] Mar 6 09:39:26 localhost kernel: skb: pf=2 (unowned) dev=eth0 len=40
] Mar 6 09:39:26 localhost kernel: PROTO=6 141.166.179.88:1323 130.205.0.20:80 L=40 S=0x00 I=48398 F=0x4000 T=117
] Mar 6 09:39:26 localhost kernel: ip_finish_output: bad owned skb = c137ff20:
] Mar 6 09:39:26 localhost kernel: skb: pf=2 (owned) dev=eth0 len=40
] Mar 6 09:39:26 localhost kernel: PROTO=6 130.205.0.20:80 141.166.179.88:1323 L=40 S=0x00 I=0 F=0x4000 T=255

        I may have to drop back before I fill my var spool system. It's
accumulating at a frightening rate.

> The hard IRQ might be because I'm using a USB modem. I think the USB
> ACM driver might be calling ppp code from irq context which is called
> from bh context by the standard serial driver.

        I'm not using a USB modem and I'm not seeing the "hard IRQ" messages.
I am using a USB mouse, but I don't think that has anything to do with the
bad skb messages for eth0 and lo0. I'm not using PPP on this system.

> -- Jamie
>
> Mar 5 23:55:20 thefinal kernel: ip_local_deliver: bad non-lo skb:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (unowned) dev=ppp0 len=96
> Mar 5 23:55:20 thefinal kernel: PROTO=6 137.138.38.126:22 213.228.27.210:1033 L=96 S=0x10 I=37133 F=0x4000 T=50
> Mar 5 23:55:20 thefinal kernel: ip_finish_output: bad owned skb = c2123180:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (owned) dev=ppp0 len=52
> Mar 5 23:55:20 thefinal kernel: PROTO=6 213.228.27.210:1033 137.138.38.126:22 L=52 S=0x10 I=0 F=0x4000 T=64
> Mar 5 23:55:20 thefinal kernel: Warning: kfree_skb on hard IRQ c4a9de69
> Mar 5 23:55:20 thefinal kernel: ip_local_deliver: bad non-lo skb:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (unowned) dev=ppp0 len=64
> Mar 5 23:55:20 thefinal kernel: PROTO=6 137.138.38.126:22 213.228.27.210:1033 L=64 S=0x10 I=37134 F=0x4000 T=50
> Mar 5 23:55:20 thefinal kernel: ip_finish_output: bad owned skb = c2123600:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (owned) dev=ppp0 len=52
> Mar 5 23:55:20 thefinal kernel: PROTO=6 213.228.27.210:1033 137.138.38.126:22 L=52 S=0x10 I=0 F=0x4000 T=64
> Mar 5 23:55:20 thefinal kernel: ip_finish_output: bad owned skb = c3ea03e0:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (owned) dev=ppp0 len=64
> Mar 5 23:55:20 thefinal kernel: PROTO=6 213.228.27.210:1033 137.138.38.126:22 L=64 S=0x08 I=0 F=0x4000 T=64
> Mar 5 23:55:20 thefinal kernel: ip_local_deliver: bad non-lo skb:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (unowned) dev=ppp0 len=54
> Mar 5 23:55:20 thefinal kernel: PROTO=6 137.138.38.126:4241 213.228.27.210:79 L=54 S=0x00 I=37135 F=0x4000 T=50
> Mar 5 23:55:20 thefinal kernel: ip_finish_output: bad owned skb = c2123300:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (owned) dev=ppp0 len=52
> Mar 5 23:55:20 thefinal kernel: PROTO=6 213.228.27.210:79 137.138.38.126:4241 L=52 S=0x00 I=0 F=0x4000 T=64
> Mar 5 23:55:20 thefinal kernel: ip_finish_output: bad owned skb = c2123300:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (owned) dev=ppp0 len=392
> Mar 5 23:55:20 thefinal kernel: PROTO=6 213.228.27.210:79 137.138.38.126:4241 L=392 S=0x00 I=0 F=0x4000 T=64
> Mar 5 23:55:20 thefinal kernel: ip_finish_output: bad owned skb = c2123000:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (owned) dev=ppp0 len=52
> Mar 5 23:55:20 thefinal kernel: PROTO=6 213.228.27.210:79 137.138.38.126:4241 L=52 S=0x00 I=0 F=0x4000 T=64
> Mar 5 23:55:20 thefinal kernel: Warning: kfree_skb on hard IRQ c4a9de69
> Mar 5 23:55:20 thefinal kernel: Warning: kfree_skb on hard IRQ c4a9de69
> Mar 5 23:55:20 thefinal kernel: ip_local_deliver: bad non-lo skb:
> Mar 5 23:55:20 thefinal kernel: skb: pf=2 (unowned) dev=ppp0 len=52
> Mar 5 23:55:20 thefinal kernel: PROTO=6 137.138.38.126:22 213.228.27.210:1034 L=52 S=0x10 I=37136 F=0x4000 T=50

        Mike

-- 
 Michael H. Warfield    |  (770) 985-6132   |  mhw@WittsEnd.com
  (The Mad Wizard)      |  (770) 331-2437   |  http://www.wittsend.com/mhw/
  NIC whois:  MHW9      |  An optimist believes we live in the best of all
 PGP Key: 0xDF1DD471    |  possible worlds.  A pessimist is sure of it!

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