[Unionfs] Can't mount NFS-exported union anymore in unionfs-1.4

[Wilhelm Meier]

Am Dienstag, 28. November 2006 16:18 schrieb hooanon05 at yahoo.co.jp:
> Wilhelm Meier:
> > > Do you mind my sending patches and remote debugging?
> > > If I send you
> > > another debug print patch, will you apply and test it?
> >
> > Yes, sure.
>
> Thank you.
> Here is a debug print patch, in order to know where in read_uin() the
> problem happend. Please apply after (over) my last patch.
> I expect the result will be,
>
> unionfs_interpose: c2c70648, b0, hi3158
> read_uin: c2c70648, b0, i3158 f0x40, c1633e3c
> read_uin:543
> read_uin:549
> read_uin:558
> read_uin:565: out

Here it comes:

unionfs_interpose: c126c800, b0, hi425997
read_uin: c126c800, b0, i425997 f0x40, cfd10ca4
read_uin:543
BUG: unable to handle kernel NULL pointer dereference at virtual address 
00000008
 printing eip:
d0a0c27b
*pde = 00000000
Oops: 0000 [#1]
SMP
Modules linked in: unionfs nfsd exportfs floppy parport_pc parport pcspkr 
pcnet32 mii mptspi mptscsih mptbase scsi_transport_spi rtc nfs lockd sunrpc 
raid10 raid1 raid0 dm_mirror dm_mod pdc_adma sata_mv ata_piix ahci sata_qstor 
sata_vsc sata_uli sata_sis sata_sx4 sata_nv sata_via sata_svw sata_sil24 
sata_sil sata_promise libata sbp2 ohci1394 ieee1394 sl811_hcd ohci_hcd 
uhci_hcd usb_storage usbhid ehci_hcd usbcore
CPU:    0
EIP:    0060:[<d0a0c27b>]    Not tainted VLI
EFLAGS: 00010246   (2.6.18-gentoo-r3 #1)
EIP is at read_uin+0xbb/0x350 [unionfs]
eax: cfd10ca4   ebx: d0a0fdf3   ecx: 0006800d   edx: 00000000
esi: 00000000   edi: d0a0fdf9   ebp: c126c84c   esp: cfd10c28
ds: 007b   es: 007b   ss: 0068
Process mount (pid: 10834, ti=cfd10000 task=cfd11000 task.ti=cfd10000)
Stack: d0a0fe16 d0a0fc3e 0000021f 00000000 0006800d 00000040 cfd10ca4 c126c84c
       cef03bc0 00000000 00000000 00000000 00340098 00000000 00000000 00000000
       d0a0fca7 00000001 d0a04835 c126c800 00000000 0006800d 00000040 cfd10ca4
Call Trace:
 [<d0a04835>] unionfs_interpose+0xd5/0x510 [unionfs]
 [<d0a0b1b5>] new_dentry_private_data+0x125/0x1c0 [unionfs]
 [<d0a053ba>] unionfs_read_super+0x6aa/0xdfc [unionfs]
 [<c0165aa9>] __d_lookup+0x95/0xdb
 [<c01d7d12>] idr_get_new_above_int+0x123/0x1fb
 [<c015f553>] __link_path_walk+0xb07/0xc56
 [<c01d7df9>] idr_get_new+0xf/0x30
 [<c0168994>] get_filesystem+0x12/0x31
 [<c0157bd3>] sget+0x2ac/0x2b6
 [<c01583c5>] get_sb_nodev+0x4e/0x91
 [<d0a04d10>] unionfs_read_super+0x0/0xdfc [unionfs]
 [<c0157df1>] vfs_kern_mount+0x35/0x66
 [<d0a04d10>] unionfs_read_super+0x0/0xdfc [unionfs]
 [<c0157e5f>] do_kern_mount+0x29/0x39
 [<c016a0f8>] do_mount+0x5cf/0x647
 [<c0169380>] mntput_no_expire+0x14/0x67
 [<c015f74a>] link_path_walk+0xa8/0xb3
 [<c013c010>] filemap_nopage+0xbf/0x31b
 [<c013c0f0>] filemap_nopage+0x19f/0x31b
 [<c01447ee>] __handle_mm_fault+0x3ff/0x756
 [<c014932e>] page_add_file_rmap+0x17/0x1a
 [<c01445d0>] __handle_mm_fault+0x1e1/0x756
 [<c015e828>] putname+0x2d/0x30
 [<c013d98a>] get_page_from_freelist+0x9f/0x356
 [<c013ded6>] __get_free_pages+0x29/0x2e
 [<c0169015>] copy_mount_options+0x28/0x10b
 [<c016a1e8>] sys_mount+0x78/0xb1
 [<c010284d>] sysenter_past_esp+0x56/0x79
Code: 24 20 8b 54 24 24 8b 41 48 8b 4c 24 54 8b 34 90 8d 04 cd 30 00 00 00 89 
44 24 30 31 c0 89 44 24 34 8b 44 24 5c c7 00 00 00 00 00 <8b> 46 08 8b 54 24 
30 8b 4c 24 34 8b 40 0c 83 c2 08 83 d1 00 3b
EIP: [<d0a0c27b>] read_uin+0xbb/0x350 [unionfs] SS:ESP 0068:cfd10c28

-- 
Wilhelm Meier
email: wilhelm.meier at fh-kl.de