OOPS from ext3_follow_link in 2.6.7+BK

OOPS from ext3_follow_link in 2.6.7+BK

[Meelis Roos]

Today evenings BK snapshot oopsed on starting X:

Unable to handle kernel paging request at virtual address 2601c78c
 printing eip:
c018d17c
*pde = 00000000
Oops: 0002 [#1]
PREEMPT
Modules linked in: binfmt_misc md5 ipv6 ipt_MASQUERADE iptable_nat ipt_REJECT ipt_LOG ipt_state ip_conntrack iptable_filter ip_tables cls_u32 sch_sfq sch_cbq usb_storage snd_bt87x uhci_hcd usbcore vfat fat md dm_mod eeprom via686a i2c_sensor parport_pc lp parport snd_via82xx snd_mpu401_uart snd_ens1371 snd_rawmidi snd_seq_device snd_pcm_oss snd_mixer_oss snd_pcm snd_page_alloc snd_timer snd_ac97_codec snd sd_mod scsi_mod mga ide_cd cdrom floppy tuner tvaudio msp3400 bttv video_buf v4l2_common btcx_risc videodev soundcore analog gameport joydev 8139too mii
CPU:    0
EIP:    0060:[<c018d17c>]    Not tainted
EFLAGS: 00010282   (2.6.7)
EIP is at ext3_follow_link+0xc/0x50
eax: d4643614   ebx: c02e9500   ecx: d4643580   edx: d470ef1c
esi: d47249bc   edi: d470ef1c   ebp: 00000400   esp: d470ef10
ds: 007b   es: 007b   ss: 0068
Process X (pid: 2752, threadinfo=d470e000 task=d7974090)
Stack: c01594ff c0113c86 bffff8d0 d470ef70 d7fbd160 d47249bc 00003cb7 d7bcb009
       00000001 d7fca400 d4643614 40db5aa4 0eeccb38 d4643650 c0161f48 40db5aa4
       0eeccb38 40db5aa4 0eeccb38 c02e9500 00000400 d4643614 d470ef70 c0152fcd
Call Trace:
 [<c01594ff>] generic_readlink+0x2f/0x80
 [<c0113c86>] do_page_fault+0x2e6/0x4c1
 [<c0161f48>] update_atime+0xb8/0xc0
 [<c0152fcd>] sys_readlink+0x9d/0xb0
 [<c0103e75>] sysenter_past_esp+0x52/0x71
Code: 89 4c 82 20 31 c0 c3 90 90 90 90 90 90 90 90 90 90 90 90 90

-- 
Meelis Roos (mroos@linux.ee)

Re: OOPS from ext3_follow_link in 2.6.7+BK

[viro]

On Fri, Jun 25, 2004 at 01:57:27AM +0300, Meelis Roos wrote:
> Call Trace:
>  [<c01594ff>] generic_readlink+0x2f/0x80

--- fs/namei.c	Thu Jun 24 16:06:45 2004
+++ fs/namei.c-fix	Thu Jun 24 16:07:24 2004
@@ -2197,7 +2197,9 @@
 int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
 	struct nameidata nd;
-	int res = dentry->d_inode->i_op->follow_link(dentry, &nd);
+	int res;
+	nd.depth = 0;
+	res = dentry->d_inode->i_op->follow_link(dentry, &nd);
 	if (!res) {
 		res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd));
 		if (dentry->d_inode->i_op->put_link)