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linux/net/rose/rose_loopback.c
Alexey Dobriyan 891e6a9312 [ROSE]: Fix rose.ko oops on unload
Commit a3d384029a aka
"[AX.25]: Fix unchecked rose_add_loopback_neigh uses"
transformed rose_loopback_neigh var into statically allocated one.
However, on unload it will be kfree's which can't work.

Steps to reproduce:

	modprobe rose
	rmmod rose

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000008
 printing eip:
c014c664
*pde = 00000000
Oops: 0000 []
PREEMPT DEBUG_PAGEALLOC
Modules linked in: rose ax25 fan ufs loop usbhid rtc snd_intel8x0 snd_ac97_codec ehci_hcd ac97_bus uhci_hcd thermal usbcore button processor evdev sr_mod cdrom
CPU:    0
EIP:    0060:[<c014c664>]    Not tainted VLI
EFLAGS: 00210086   (2.6.23-rc9 )
EIP is at kfree+0x48/0xa1
eax: 00000556   ebx: c1734aa0   ecx: f6a5e000   edx: f7082000
esi: 00000000   edi: f9a55d20   ebp: 00200287   esp: f6a5ef28
ds: 007b   es: 007b   fs: 0000  gs: 0033  ss: 0068
Process rmmod (pid: 1823, ti=f6a5e000 task=f7082000 task.ti=f6a5e000)
Stack: f9a55d20 f9a5200c 00000000 00000000 00000000 f6a5e000 f9a5200c f9a55a00 
       00000000 bf818cf0 f9a51f3f f9a55a00 00000000 c0132c60 65736f72 00000000 
       f69f9630 f69f9528 c014244a f6a4e900 00200246 f7082000 c01025e6 00000000 
Call Trace:
 [<f9a5200c>] rose_rt_free+0x1d/0x49 [rose]
 [<f9a5200c>] rose_rt_free+0x1d/0x49 [rose]
 [<f9a51f3f>] rose_exit+0x4c/0xd5 [rose]
 [<c0132c60>] sys_delete_module+0x15e/0x186
 [<c014244a>] remove_vma+0x40/0x45
 [<c01025e6>] sysenter_past_esp+0x8f/0x99
 [<c012bacf>] trace_hardirqs_on+0x118/0x13b
 [<c01025b6>] sysenter_past_esp+0x5f/0x99
 =======================
Code: 05 03 1d 80 db 5b c0 8b 03 25 00 40 02 00 3d 00 40 02 00 75 03 8b 5b 0c 8b 73 10 8b 44 24 18 89 44 24 04 9c 5d fa e8 77 df fd ff <8b> 56 08 89 f8 e8 84 f4 fd ff e8 bd 32 06 00 3b 5c 86 60 75 0f 
EIP: [<c014c664>] kfree+0x48/0xa1 SS:ESP 0068:f6a5ef28

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-07 23:44:17 -07:00

113 lines
2.4 KiB
C

/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
*/
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/timer.h>
#include <net/ax25.h>
#include <linux/skbuff.h>
#include <net/rose.h>
#include <linux/init.h>
static struct sk_buff_head loopback_queue;
static struct timer_list loopback_timer;
static void rose_set_loopback_timer(void);
void rose_loopback_init(void)
{
skb_queue_head_init(&loopback_queue);
init_timer(&loopback_timer);
}
static int rose_loopback_running(void)
{
return timer_pending(&loopback_timer);
}
int rose_loopback_queue(struct sk_buff *skb, struct rose_neigh *neigh)
{
struct sk_buff *skbn;
skbn = skb_clone(skb, GFP_ATOMIC);
kfree_skb(skb);
if (skbn != NULL) {
skb_queue_tail(&loopback_queue, skbn);
if (!rose_loopback_running())
rose_set_loopback_timer();
}
return 1;
}
static void rose_loopback_timer(unsigned long);
static void rose_set_loopback_timer(void)
{
del_timer(&loopback_timer);
loopback_timer.data = 0;
loopback_timer.function = &rose_loopback_timer;
loopback_timer.expires = jiffies + 10;
add_timer(&loopback_timer);
}
static void rose_loopback_timer(unsigned long param)
{
struct sk_buff *skb;
struct net_device *dev;
rose_address *dest;
struct sock *sk;
unsigned short frametype;
unsigned int lci_i, lci_o;
while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
lci_i = ((skb->data[0] << 8) & 0xF00) + ((skb->data[1] << 0) & 0x0FF);
frametype = skb->data[2];
dest = (rose_address *)(skb->data + 4);
lci_o = 0xFFF - lci_i;
skb_reset_transport_header(skb);
sk = rose_find_socket(lci_o, rose_loopback_neigh);
if (sk) {
if (rose_process_rx_frame(sk, skb) == 0)
kfree_skb(skb);
continue;
}
if (frametype == ROSE_CALL_REQUEST) {
if ((dev = rose_dev_get(dest)) != NULL) {
if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0)
kfree_skb(skb);
} else {
kfree_skb(skb);
}
} else {
kfree_skb(skb);
}
}
}
void __exit rose_loopback_clear(void)
{
struct sk_buff *skb;
del_timer(&loopback_timer);
while ((skb = skb_dequeue(&loopback_queue)) != NULL) {
skb->sk = NULL;
kfree_skb(skb);
}
}