Kernel panic with NFSD

[GoogleCodeExporter]

What steps will reproduce the problem?
1.Activate NFS with a USB storage

What is the expected output? What do you see instead?
To see the kernel panic log, tail -f /tmp/syslog.log until the kernel panic. 
Here is the crash:

Jan  1 00:02:02 kernel: CPU 0 Unable to handle kernel paging request at virtual 
address 67ffffd4, epc == 800a95c4, ra == c07607b8
Jan  1 00:02:02 kernel: Oops[#1]:
Jan  1 00:02:02 kernel: Cpu 0
Jan  1 00:02:02 kernel: $ 0   : 00000000 00000000 a000010e 00000001
Jan  1 00:02:02 kernel: $ 4   : a000010e 00030d6e 00030d6e 00000000
Jan  1 00:02:02 kernel: $ 8   : 00000000 00000000 c065aa98 80301090
Jan  1 00:02:02 kernel: $12   : ffffffff 00000000 00000000 ffffffff
Jan  1 00:02:02 kernel: $16   : a000010e a000019a 67ffff88 86eb4c80
Jan  1 00:02:02 kernel: $20   : c07859e8 00000001 00000002 86fd9018
Jan  1 00:02:02 kernel: $24   : 00000000 800a9578
Jan  1 00:02:02 kernel: $28   : 8284a000 8284bbf8 c0790000 c07607b8
Jan  1 00:02:02 kernel: Hi    : 0000001c
Jan  1 00:02:02 kernel: Lo    : 8b0d7800
Jan  1 00:02:02 kernel: epc   : 800a95c4 0x800a95c4
Jan  1 00:02:02 kernel:     Tainted: P
Jan  1 00:02:02 kernel: ra    : c07607b8 0xc07607b8
Jan  1 00:02:02 kernel: Status: 1100ff03    KERNEL EXL IE
Jan  1 00:02:02 kernel: Cause : 00800008
Jan  1 00:02:02 kernel: BadVA : 67ffffd4
Jan  1 00:02:02 kernel: PrId  : 0001974c (MIPS 74Kc)
Jan  1 00:02:02 kernel: Modules linked in: nfsd exportfs lockd sunrpc ufsd(P) 
hw_nat(P) nf_nat_ftp nf_conntrack_ftp ohci_hcd ehci_hcd usb_storage usblp 
rt3090_ap rt2860v2_ap(P)
Jan  1 00:02:02 kernel: Process nfsd (pid: 634, threadinfo=8284a000, 
task=86f12978, tls=00000000)
Jan  1 00:02:02 kernel: Stack : 86f5bdf0 00000000 86f5b000 00000000 ffffff69 
c0658ef8 87c0da90 c07607b8
Jan  1 00:02:02 kernel:         00000001 86f12978 800494f0 00100100 00200200 
82879200 00000001 c0794144
Jan  1 00:02:02 kernel:         82879200 82853980 c0794144 87c0da90 878fe858 
c0794b90 8284bcd0 c078a4f8
Jan  1 00:02:02 kernel:         00000000 8284bc84 8284bc84 00000000 00000000 
8284bc6c 8284bc6c 82879200
Jan  1 00:02:02 kernel:         80301c60 c0727774 00000000 8284bc84 8284bc84 
82853980 000000f2 86fd9010
Jan  1 00:02:02 kernel:         ...
Jan  1 00:02:02 kernel: Call Trace:[<c07607b8>] 0xc07607b8
Jan  1 00:02:02 kernel: [<800494f0>] 0x800494f0
Jan  1 00:02:02 kernel: [<c078a4f8>] 0xc078a4f8
Jan  1 00:02:02 kernel: [<c0727774>] 0xc0727774
Jan  1 00:02:02 kernel: [<c0790000>] 0xc0790000
Jan  1 00:02:02 kernel: [<c078bd30>] 0xc078bd30
Jan  1 00:02:02 kernel: [<8004c0b8>] 0x8004c0b8
Jan  1 00:02:02 kernel: [<8004c140>] 0x8004c140
Jan  1 00:02:02 kernel: [<8002f4a8>] 0x8002f4a8
Jan  1 00:02:02 kernel: [<c0790000>] 0xc0790000
Jan  1 00:02:02 kernel: [<c0785f34>] 0xc0785f34
Jan  1 00:02:02 kernel: [<c07859e8>] 0xc07859e8
Jan  1 00:02:02 kernel: [<c0727954>] 0xc0727954
Jan  1 00:02:02 kernel: [<c0788844>] 0xc0788844
Jan  1 00:02:02 kernel: [<80060518>] 0x80060518
Jan  1 00:02:02 kernel: [<8002900c>] 0x8002900c
Jan  1 00:02:02 kernel: [<8011a5e0>] 0x8011a5e0
Jan  1 00:02:02 kernel: [<802a0308>] 0x802a0308
Jan  1 00:02:02 kernel: [<c0790000>] 0xc0790000
Jan  1 00:02:02 kernel: [<c0790214>] 0xc0790214
Jan  1 00:02:02 kernel: [<8011a5e0>] 0x8011a5e0
Jan  1 00:02:02 kernel: [<c078244c>] 0xc078244c
Jan  1 00:02:02 kernel: [<8002941c>] 0x8002941c
Jan  1 00:02:02 kernel: [<c071bad0>] 0xc071bad0
Jan  1 00:02:02 kernel: [<c072b724>] 0xc072b724
Jan  1 00:02:02 kernel: [<c071b690>] 0xc071b690
Jan  1 00:02:02 kernel: [<c0782d88>] 0xc0782d88
Jan  1 00:02:02 kernel: [<802a0718>] 0x802a0718
Jan  1 00:02:02 kernel: [<c0782bf8>] 0xc0782bf8
Jan  1 00:02:02 kernel: [<8003ebcc>] 0x8003ebcc
Jan  1 00:02:02 kernel: [<8000b240>] 0x8000b240
Jan  1 00:02:02 kernel: [<8003eb44>] 0x8003eb44
Jan  1 00:02:02 kernel: [<8000b230>] 0x8000b230
Jan  1 00:02:02 kernel: Code: 0802a574  00009021  2652ff88 <8e42004c> 24420001  
ae42004c  16400028  3c05802b  8e040014

What version of the product are you using? On what operating system?
Router: Asus RT-N56U (tested on two different unit, one brand new)
USB Storage: 2Tb External Hard Disk on NTFS
Tested OS: 
3.4.3.8-085-base -> Kernel Panic
3.4.3.8-085-aria -> Kernel Panic
3.0.3.8-081-base -> Kernel Panic

Really the problem seems to be with NFS. Whenever I start the process, the 
router will kernel panic each 3 to 5 minutes. When I disable back NFS, the 
router is stable. I had an old firmware that NFS was running fine, but since I 
had upgraded to recent firmware, NFS keep crashing. Unfortunately, I don't 
remember the version I was running with NFS working. Don't hesitate if you need 
more information.

Thank you for the awesome firmware.

Original issue reported on code.google.com by jonielga...@gmail.com on 31 Oct 2014 at 3:07

[GoogleCodeExporter]

> Really the problem seems to be with NFS.

Nope, the problem is with NTFS on your hdd.
first try running chkdsk on your windows machine.

NTFS is NOT recommended, because NTFS driver is a binary blob, there are no 
sources for it, therefore it can not be fixed.

If you want to use NFS you should format your hdd with extX filesystem.

Original comment by irher...@gmail.com on 7 Nov 2014 at 2:26

[GoogleCodeExporter]

Hi,

well it seems your right, I have format my disk with EXT3 and it rocks NFS 
transfer for more than an hour without any kernel panic. I hate Microsoft 
because of those kind of things...

Thx for your help.

Original comment by jonielga...@gmail.com on 10 Nov 2014 at 10:49

[GoogleCodeExporter]

That's not the fault of Microsoft, but the problem of ufsd driver for NTFS in 
Linux. So NTFS is not recommended on this device. It's always better to use 
'native' OS filesystems - EXT on Linux.
By the way, XFS seems to become stable. It's much faster than EXT and probably 
will become one of the native FS.

PS: ZFS rules anyway ;)

Original comment by serge...@gmail.com on 11 Nov 2014 at 5:25