Hi Guys n Gals
This is suresh kumar Rathod Kethavath from Bangalore, India
Have a glance to this code which is part of tcp_output.c
377 err = tp->af_specific->queue_xmit(skb, 0);
378 printk(KERN_ALERT "\n transmitted skb : "); /*modified */
379 /* err = tp->af_specific->queue_xmit(skb1, 0); modified */
380 if (err <= 0)
381 {
382 err = tp->af_specific->queue_xmit(skb1, 0); /* modified */
383 printk(KERN_ALERT "\n transmitted skb1 : "); /*modified */
384 return err;
385 }
err value is always 0 for my context
my objective is to make a copy os skb and re transmit it immediately
os after transmiting one copy, I was unable to send the nest which is in if block
the error repoted in /var/log/messages is as fallows
May 25 18:18:17 localhost kernel: uhci_hcd 0000:00:1d.2: UHCI Host Controller
May 25 18:18:17 localhost kernel: uhci_hcd 0000:00:1d.2: irq 169, io base 0x2480
May 25 18:18:17 localhost kernel: uhci_hcd 0000:00:1d.2: new USB bus registered, assigned bus n
umber 4
May 25 18:18:17 localhost kernel: hub 4-0:1.0: USB hub found
May 25 18:18:17 localhost kernel: hub 4-0:1.0: 2 ports detected
May 25 18:18:17 localhost kernel:
May 25 18:18:17 localhost kernel: In tcp_transmit_skb() :<1>
May 25 18:18:17 localhost kernel: copied skb is : 152<1>
May 25 18:18:17 localhost kernel: in ip_queue_xmit():<1>
May 25 18:18:17 localhost kernel: in ip_queue_xmit()buldng iphdr:<1>
May 25 18:18:17 localhost kernel: in ip_queue_xmit()checksumng :<1>
May 25 18:18:17 localhost kernel: in ip_queue_xmit()tbout2hook:<1>
May 25 18:18:17 localhost kernel: transmitted skb : <1>Unable to handle kernel NULL pointer de
reference at virtual address 00000194
May 25 18:18:17 localhost kernel: printing eip:
May 25 18:18:17 localhost kernel: c02b4f71
May 25 18:18:17 localhost kernel: *pde = 1d6ae001
May 25 18:18:17 localhost kernel: Oops: 0000 [#1]
May 25 18:18:17 localhost kernel: SMP DEBUG_PAGEALLOC
May 25 18:18:17 localhost kernel: Modules linked in: uhci_hcd ehci_hcd i2c_i801 i2c_core tg3 81
39too mii floppy ext3 jbd scsi_mod
May 25 18:18:17 localhost kernel: CPU: 0
May 25 18:18:17 localhost kernel: EIP: 0060:[<c02b4f71>] Not tainted VLI
May 25 18:18:17 localhost kernel: EFLAGS: 00010286 (2.6.11CMMACS)
May 25 18:18:17 localhost kernel: EIP is at ip_queue_xmit+0x11/0x4e0
May 25 18:18:17 localhost kernel: eax: dea36f60 ebx: 00000000 ecx: c036b320 edx: 00000000
May 25 18:18:17 localhost kernel: esi: dea36f60 edi: 00000000 ebp: df2c4d88 esp: df2c4d14
May 25 18:18:18 localhost kernel: ds: 007b es: 007b ss: 0068
May 25 18:18:18 localhost kernel: Process rhgb (pid: 1202, threadinfo=df2c4000 task=dd79bab0)
May 25 18:18:18 localhost kernel: Stack: 0002ca7b df2c4d38 c0124317 00020000 00000000 0000ca7d 0002ca91 0002ca91
May 25 18:18:18 localhost kernel: 00000286 df2c4d54 c012479c dea36f60 fffe0000 c0427657 c0427656 00000000
May 25 18:18:18 localhost kernel: df2c4d74 c0124658 df2c4d94 00000286 00000017 00000000 dbb5cba8 dea36f60
May 25 18:18:18 localhost kernel: Call Trace:
May 25 18:18:18 localhost kernel: [<c0104f56>] show_stack+0xa6/0xe0
May 25 18:18:18 localhost kernel: [<c0105116>] show_registers+0x166/0x200
May 25 18:18:18 localhost hcid[1817]: Bluetooth HCI daemon
May 25 18:18:18 localhost kernel: [<c0105349>] die+0xf9/0x190
May 25 18:18:18 localhost sdpd[1819]: init_server: opening L2CAP socket: Address family not supported by protocol
May 25 18:18:18 localhost hcid[1817]: Can't open HCI socket: Address family not supported by protocol (97)
May 25 18:18:18 localhost kernel: [<c011b382>] do_page_fault+0x242/0x75e
May 25 18:18:18 localhost sdpd[1819]: main: Server initialization failed
May 25 18:18:18 localhost kernel: [<c0104b9f>] error_code+0x2b/0x30
May 25 18:18:18 localhost kernel: [<c02c654d>] tcp_transmit_skb+0x74d/0x810
May 25 18:18:18 localhost kernel: [<c02c8cfd>] tcp_connect+0x28d/0x370
May 25 18:18:18 localhost kernel: [<c02cba4d>] tcp_v4_connect+0x55d/0xa50
May 25 18:18:18 localhost kernel: [<c02daf95>] inet_stream_connect+0x95/0x170
May 25 18:18:18 localhost kernel: [<c029311a>] sys_connect+0x5a/0x80
May 25 18:18:18 localhost kernel: [<c02939f4>] sys_socketcall+0x94/0x260
May 25 18:18:18 localhost kernel: [<c010402d>] sysenter_past_esp+0x52/0x75
May 25 18:18:18 localhost kernel: Code: 78 08 00 74 08 5d 89 c8 e9 5d fc ff ff 5d ba b0 4b 2b c0 89 c8 e9 80 05 00 00 55 89 e5 57 56 89 c6 53 83 ec 68 89 55 9c 8b 78 0c <8b> 87 94 01 00 00 c7 04 24 51 dc 32 c0 89 45 a0 e8 6a f5 e6 ff
May 25 18:18:56 localhost kernel: Call Trace:
May 25 18:18:56 localhost kernel: [<c0104f56>] show_stack+0xa6/0xe0
May 25 18:18:56 localhost kernel: [<c0105116>] show_registers+0x166/0x200
May 25 18:18:56 localhost kernel: [<c0105349>] die+0xf9/0x190
May 25 18:18:56 localhost kernel: [<c011b382>] do_page_fault+0x242/0x75e
May 25 18:18:56 localhost kernel: [<c0104b9f>] error_code+0x2b/0x30
May 25 18:18:56 localhost kernel: [<c02c654d>] tcp_transmit_skb+0x74d/0x810
May 25 18:18:57 localhost kernel: [<c02c8cfd>] tcp_connect+0x28d/0x370
May 25 18:18:57 localhost kernel: [<c02cba4d>] tcp_v4_connect+0x55d/0xa50
May 25 18:18:57 localhost kernel: [<c02daf95>] inet_stream_connect+0x95/0x170
May 25 18:18:57 localhost kernel: [<c029311a>] sys_connect+0x5a/0x80
May 25 18:18:57 localhost kernel: [<c02939f4>] sys_socketcall+0x94/0x260
May 25 18:18:57 localhost kernel: [<c0104083>] syscall_call+0x7/0xb
May 25 18:18:57 localhost kernel: Code: 78 08 00 74 08 5d 89 c8 e9 5d fc ff ff 5d ba b0 4b 2b c0 89 c8 e9 80 05 00 00 55 89 e5 57 56 89 c6 53 83 ec 68 89 55 9c 8b 78 0c <8b> 87 94 01 00 00 c7 04 24 51 dc 32 c0 89 45 a0 e8 6a f5 e6 ff
May 25 18:19:05 localhost kernel: <6>
May 25 18:19:05 localhost kernel: In tcp_transmit_skb() :<1>
May 25 18:19:05 localhost kernel: copied skb is : 152<1>
May 25 18:19:05 localhost kernel: in ip_queue_xmit():<1>
May 25 18:19:05 localhost kernel: in ip_queue_xmit()buldng iphdr:<1>
May 25 18:19:05 localhost kernel: in ip_queue_xmit()checksumng :<1>
May 25 18:19:05 localhost kernel: in ip_queue_xmit()tbout2hook:<1>
May 25 18:19:05 localhost kernel: transmitted skb : <1>Unable to handle kernel NULL pointer dereference at virtual address 00000194
May 25 18:19:05 localhost kernel: printing eip:
May 25 18:19:05 localhost kernel: c02b4f71
On Thu, 25 May 2006 Sven Schuster wrote :
>On Thu, May 25, 2006 at 02:32:02PM +0530, Abu M. Muttalib told us:
> > Thanks Sven.
>
>On Thu, May 25, 2006 at 05:26:02PM +0800, cheng long told us:
> > Great News !
> >
> > Thanks most sincerely!
> >
> > Cheng
> >
>
>You're welcome :-)
>
>
>Sven
>
>--
>Linux zion.homelinux.com 2.6.17-rc4-mm1_34 #34 Tue May 16 00:28:18 CEST 2006 i686 athlon i386 GNU/Linux
> 14:31:52 up 8 days, 14:51, 2 users, load average: 0.05, 0.13, 0.09
