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RE: skb allocation problems (More Brain damage!)

To: ak@xxxxxxx, Imran.Patel@xxxxxxxxx
Subject: RE: skb allocation problems (More Brain damage!)
From: Imran.Patel@xxxxxxxxx
Date: Wed, 11 Apr 2001 20:15:49 +0300
Cc: netfilter-devel@xxxxxxxxxxxxx, netdev@xxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx
Sender: owner-netdev@xxxxxxxxxxx
> Well, I don't know then. You have to debug it. It's probably 
> something stupid
> (if fundamental services like alloc_skb/kfree_skb were 
> completely buggy
> someone surely would have noticed earlier)

yep, at first i thought it was because of sume stupidity in my module...but
now it seems that actually it is not my code which is doing something
stupid....just now i have found out that even simple ping faces similar
problems ....here is the output that i get when i ping from the host
192.168.102.29 (runs 2.4.1) to 192.168.102.22 (runs 2.4.3) (Note:I don't
insert any kernel modules of my own on these machines):


PING 192.168.102.22 (192.168.102.22) from 192.168.102.29 : 100(128) bytes of
data.
108 bytes from hobbes.sr.ntc.nokia.com (192.168.102.22): icmp_seq=0 ttl=255
time=36.5 ms
wrong data byte #36 should be 0x24 but was 0x45
        19 45 d4 3a e 7a a 0 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19
1a 1b 1c 1d 1e 1f 
        20 21 22 23 45 0 0 80 0 0 40 0 ff 1 2d f8 c0 a8 66 16 c0 a8 66 1d 0
0 0 0 4 c 0 0 
        19 45 d4 3a e 7a a 0 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19
1a 1b 

--- 192.168.102.22 ping statistics ---
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 36.5/36.5/36.5 ms


Note that the problem starts with byte #36 which goes on like " 45 0 0 80 0
......." which is in fact the outer IP header!! So certainly there are
buffer overruns on the other end (host 192.168.102.22)....

And as a I said earlier, only ping packets with size within certain range
create this problem......Something is terribly wrong here!! But as I am not
a Linux mm guru, i can't tell what is wrong here!


regards,
imran


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