BUG: unable to handle kernel NULL pointer dereference at 0000000000000010, set_nfsv4_acl_one+0x21/0xb0 [nfsd]

[Sergio Gelato]

I've seen this happen twice in the last 8 days on an NFS server running Ubuntu precise and kernels 3.2.0-65.98-generic (on the first occasion) and 3.2.0-67.101-generic (the second time), amd64. This never happened before in several months of operation; until 2014-07-01 this server was running an older 3.2.0 kernel.

When this error appears in the logs, the system stops answering NFS RPCs (e.g., "rpcinfo -u localhost nfs 3" hangs) and a reboot is necessary to restore NFS service. A more detailed stack trace follows. Looking at the source code (fs/nfsd/vfs.c:set_nfsv4_acl_one()) I see that the call posix_acl_xattr_size(pacl->a_count) is not preceded by a check that pacl != NULL. Could this be related to the following entry in the changelog for 3.2.0-65.98?

  * NFSD: Call ->set_acl with a NULL ACL structure if no entries
    - LP: #1328154

Jul 24 10:12:53 server kernel: [575939.742131] IP: [<ffffffffa055c451>] set_nfsv4_acl_one+0x21/0xb0 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] PGD c243bb067 PUD c2400a067 PMD 0
Jul 24 10:12:53 server kernel: [575939.742131] Oops: 0000 [#1] SMP
Jul 24 10:12:53 server kernel: [575939.742131] CPU 3
Jul 24 10:12:53 server kernel: [575939.742131] Modules linked in: usblp btrfs zlib_deflate libcrc32c ufs qnx4 hfsplus hfs minix ntfs vfat msdos fat jfs reiserfs ext2 cts openafs(P) xt_tcpudp ipmi_si ipmi_devintf ipmi_msghandler iptable_filter ip_tables x_tables autofs4 bnep parport_pc rfcomm bluetooth ppdev binfmt_misc rpcsec_gss_krb5 nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc xfs dm_crypt bridge stp psmouse hpilo sp5100_tco i2c_piix4 amd64_edac_mod hpwdt edac_core k10temp edac_mce_amd joydev serio_raw acpi_power_meter mac_hid lp parport raid10 raid456 async_pq async_xor xor async_memcpy async_raid6_recov raid6_pq async_tx raid1 raid0 multipath linear radeon ttm drm_kms_helper drm osst usbhid hid st ch i2c_algo_bit pata_atiixp hpsa bnx2
Jul 24 10:12:53 server kernel: [575939.742131]
Jul 24 10:12:53 server kernel: [575939.742131] Pid: 2523, comm: nfsd Tainted: P O 3.2.0-67-generic #101-Ubuntu HP ProLiant DL385 G7
Jul 24 10:12:53 server kernel: [575939.742131] RIP: 0010:[<ffffffffa055c451>] [<ffffffffa055c451>] set_nfsv4_acl_one+0x21/0xb0 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] RSP: 0018:ffff880422085ce0 EFLAGS: 00010282
Jul 24 10:12:53 server kernel: [575939.742131] RAX: 0000000000004000 RBX: ffff880e29b16cc0 RCX: 00000000013cc2cc
Jul 24 10:12:53 server kernel: [575939.742131] RDX: ffffffffa0583374 RSI: 0000000000000000 RDI: ffff880e29b16cc0
Jul 24 10:12:53 server kernel: [575939.742131] RBP: ffff880422085d10 R08: ffffea002cdf3b80 R09: ffffffffa055c4af
Jul 24 10:12:53 server kernel: [575939.742131] R10: ffff880b37ceed00 R11: 0000000040000004 R12: 0000000000000000
Jul 24 10:12:53 server kernel: [575939.742131] R13: ffff8807f56418c0 R14: 0000000000000000 R15: ffff880c2268d180
Jul 24 10:12:53 server kernel: [575939.742131] FS: 00007fbbbbafd700(0000) GS:ffff88103fc80000(0000) knlGS:0000000000000000
Jul 24 10:12:53 server kernel: [575939.742131] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Jul 24 10:12:53 server kernel: [575939.742131] CR2: 0000000000000010 CR3: 0000000c22d6c000 CR4: 00000000000006e0
Jul 24 10:12:53 server kernel: [575939.742131] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Jul 24 10:12:53 server kernel: [575939.742131] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Jul 24 10:12:53 server kernel: [575939.742131] Process nfsd (pid: 2523, threadinfo ffff880422084000, task ffff880425964500)
Jul 24 10:12:53 server kernel: [575939.742131] Stack:
Jul 24 10:12:53 server kernel: [575939.742131] ffff880c2268d040 ffff880e29b16cc0 0000000000000000 ffff8807f56418c0
Jul 24 10:12:53 server kernel: [575939.742131] 0000000000000000 ffff880c2268d180 ffff880422085d50 ffffffffa055d5e3
Jul 24 10:12:53 server kernel: [575939.742131] ffff880b37cee840 0000000000000000 ffff880c22684000 ffff880c2268d040
Jul 24 10:12:53 server kernel: [575939.742131] Call Trace:
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa055d5e3>] nfsd4_set_nfs4_acl+0x143/0x150 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa056ab74>] nfsd4_setattr+0xd4/0x130 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa0569be8>] nfsd4_proc_compound+0x518/0x6e0 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa0558a4b>] nfsd_dispatch+0xeb/0x230 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa03ae475>] svc_process_common+0x345/0x690 [sunrpc]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffff81060ad0>] ? try_to_wake_up+0x200/0x200
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa03aeb12>] svc_process+0x102/0x150 [sunrpc]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa05581ad>] nfsd+0xbd/0x160 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffffa05580f0>] ? nfsd_startup+0xf0/0xf0 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffff8108b8cc>] kthread+0x8c/0xa0
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffff8166deb4>] kernel_thread_helper+0x4/0x10
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffff8108b840>] ? flush_kthread_worker+0xa0/0xa0
Jul 24 10:12:53 server kernel: [575939.742131] [<ffffffff8166deb0>] ? gs_change+0x13/0x13
Jul 24 10:12:53 server kernel: [575939.742131] Code: 19 c0 f7 d0 83 e0 02 c3 90 90 55 48 89 e5 48 83 ec 30 48 89 5d d8 4c 89 65 e0 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 66 66 66 66 90 <48> 63 46 10 49 89 fd 49 89 f6 be d0 00 00 00 49 89 d4 4c 8d 3c
Jul 24 10:12:53 server kernel: [575939.742131] RIP [<ffffffffa055c451>] set_nfsv4_acl_one+0x21/0xb0 [nfsd]
Jul 24 10:12:53 server kernel: [575939.742131] RSP <ffff880422085ce0>
Jul 24 10:12:53 server kernel: [575939.742131] CR2: 0000000000000010
Jul 24 10:12:53 server kernel: [575942.132715] ---[ end trace ba2b82e486b77140 ]---

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1348670

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Sergio Gelato (sergio-gelato)]

Can't run apport-collect on this server.

[Sergio Gelato (sergio-gelato)]

* Sergio Gelato [2014-07-25 14:23:03 -0000]:
> Could this be related to the following entry in the changelog
> for 3.2.0-65.98?
>
> * NFSD: Call ->set_acl with a NULL ACL structure if no entries
> - LP: #1328154

Yes, I think that's it. That change allows posix_state_to_acl() to return
NULL in some cases, and the pre-3.14 set_nfsv4_acl() code doesn't guard
against being passed a NULL for the pacl argument. From a brief perusal
of the sources I think this affects kernels 3.13 (trusty) and older.

A quick fix might be to add
 if (!pacl)
  return vfs_setxattr(dentry, key, NULL, 0, 0);
at the beginning of set_nfsv4_acl_one(). Note I haven't tested this yet.

[Harald Nordgård-Hansen (hhansen)]

It would be nice if this bug could be given some priority, it is making it hard to run precise as an nfs server. I've just spent some hours chasing down this on our systems, and can confirm that it also affects kernels 3.8.0-44 and 3.13.0-32.

It is quite easy to trigger, a 'cp -a ...' on any nfs client will kill one nfsd thread on the server. Once all threads are gone, the server is dead and must be rebooted. Restarting the nfs-kernel-server service has no effect.

[SergeiFranco (sergei-franco)]

I can confirm this bug as well. The cp -a consistently kills nfsd threads on Ubuntu Server 14.04LTS running 3.13.0-32-generic.
This is a very critical bug: "Improtance: Medium" is an understatement.

[Michiel (m-konstapel)]

Any hints at a workaround in the meantime? It's especially nasty since a dead NFS server locks up the clients completely.

[Sergio Gelato (sergio-gelato)]

* Michiel [2014-08-07 10:58:29 -0000]:
> Any hints at a workaround in the meantime? It's especially nasty since a
> dead NFS server locks up the clients completely.

I'd say either test my suggested patch (I'm on holiday and haven't gotten
around to testing, but since it only modifies the code path that triggers
the bug you should be pretty safe from side effects) or try nfsd.ko from an
older kernel.

[fs-physik-bielefeld (ubuntu-fachschaft)]

Had the same problem and at the moment I worked around it by downgrading to linux-image-3.2.0-60-generic. Of course this is not a permanent solution, especially since I probably can not do the long expected upgrade from 12.04 to 14.04 until this is fixed.

[Sergio Gelato (sergio-gelato)]

I'm now testing my one-line patch from comment #5 on top of 3.2.0-67.101
(amd64, generic kernel flavour). So far it doesn't seem to make things
worse, but since I don't have a sure-fire way of triggering the bug it
may take a while to get experimental confirmation that it cures the issue.
(I'm reasonably confident about it based on my reading of the source code,
however. The various set_acl methods in 3.14 seem to be doing the
same thing as that patch.)

[Sergio Gelato (sergio-gelato)]

* Sergio Gelato [2014-08-22 07:29:32 -0000]:
> I'm now testing my one-line patch from comment #5 on top of 3.2.0-67.101
> (amd64, generic kernel flavour). So far it doesn't seem to make things
> worse, but since I don't have a sure-fire way of triggering the bug it
> may take a while to get experimental confirmation that it cures the issue.

I've now got >9 days of uptime on two NFS servers with that patch (both servers
had been previously affected by the bug) without any trouble; not a single
nfsd thread has been lost.

Unfortunately the fix didn't make it into 3.2.0-68.102 so I'm having to
build my own kernels once more. What are the chances of this fix (or an
equivalent/better one, of course) being included in 3.2.63? I'm attaching
the patch again in diff form for clarity and convenience.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.17 kernel[0].

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.17-rc3-utopic/

[Joseph Salisbury (jsalisbury)]

Also, has the patch in comment #12 been sent upstream for inclusion in the mainline/stable kernel?

[Tim Gardner (timg-tpi)]

https://lists.ubuntu.com/archives/kernel-team/2014-September/048156.html

[Tim Gardner (timg-tpi)]

Patch submitted to the k-team list

[Sergio Gelato (sergio-gelato)]

* Joseph Salisbury [2014-09-03 19:46:04 +0000]:
> Also, has the patch in comment #12 been sent upstream for inclusion in
> the mainline/stable kernel?

The affected code was refactored out of existence in kernel 3.14. As such,
my patch is inapplicable to 3.14 and later. The replacement set_acl methods
in the various filesystem drivers generally are coded to cope with a NULL
argument; I didn't conduct an exhaustive search but I looked at a few and
didn't notice anything problematic.

Given the above, I see no need to actually test kernel 3.17. Will tag.

[Sergio Gelato (sergio-gelato)]

I'm a bit confused by Tim's changes in #16. The bug affects kernels up to and including 3.13 (trusty). I'll take his word that it also affects lucid, but what does a status of Invalid mean?

[Andy Whitcroft (apw)]

Invalid for the development release is appropriate as this code was removed in v3.14 (you indicate). This looks applicable to P and T indeed.

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-trusty' to 'verification-done-trusty'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[ScHRiLL (gorjan)]

Same error with new kernel. It was fine and working without a hick up and today the same issue reverted. 16:01:16 up 6 days

Using
3.2.0-69-generic #103-Ubuntu SMP Tue Sep 2 05:02:14 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
ii linux-image-3.2.0-69-generic 3.2.0-69.103 Linux kernel image for version 3.2.0 on 64 bit x86 SMP
ii linux-image-server 3.2.0.69.82 Linux kernel image on Server Equipment.

Oct 2 15:54:29 barbarela kernel: [528230.139053] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
Oct 2 15:54:29 barbarela kernel: [528230.139091] IP: [<ffffffffa03fb451>] set_nfsv4_acl_one+0x21/0xb0 [nfsd]
Oct 2 15:54:29 barbarela kernel: [528230.139129] PGD 415158067 PUD 415159067 PMD 0
Oct 2 15:54:29 barbarela kernel: [528230.139157] Oops: 0000 [#19] SMP
Oct 2 15:54:29 barbarela kernel: [528230.139176] CPU 1
Oct 2 15:54:29 barbarela kernel: [528230.139185] Modules linked in: it87(O) vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) pci_stub nfsd nfs lockd fscache auth_rpcgss nfs_acl sunrpc dm_crypt snd_hda_codec_hdmi snd_hda_intel snd_hda_codec psmouse edac_core lp edac_mce_amd parport sp5100_tco i2c_piix4 mac_hid k10temp serio_raw snd_hwdep snd_pcm snd_timer snd soundcore snd_page_alloc bonding hwmon_vid fam15h_power raid456 async_pq async_xor xor async_memcpy async_raid6_recov raid6_pq async_tx raid1 raid0 multipath linear raid10 nouveau ttm drm_kms_helper drm i2c_algo_bit mxm_wmi pata_atiixp r8169 video wmi [last unloaded: vboxdrv]
Oct 2 15:54:29 barbarela kernel: [528230.139546]
Oct 2 15:54:29 barbarela kernel: [528230.139557] Pid: 4409, comm: nfsd Tainted: G D O 3.2.0-69-generic #103-Ubuntu Gigabyte Technology Co., Ltd. GA-970A-DS3/GA-970A-DS3
Oct 2 15:54:29 barbarela kernel: [528230.139596] RIP: 0010:[<ffffffffa03fb451>] [<ffffffffa03fb451>] set_nfsv4_acl_one+0x21/0xb0 [nfsd]
Oct 2 15:54:29 barbarela kernel: [528230.139629] RSP: 0018:ffff8801bdc29ce0 EFLAGS: 00010282
Oct 2 15:54:29 barbarela kernel: [528230.139644] RAX: 0000000000004000 RBX: ffff88000381f480 RCX: 0000000002ae378f
Oct 2 15:54:29 barbarela kernel: [528230.139661] RDX: ffffffffa0422374 RSI: 0000000000000000 RDI: ffff88000381f480
Oct 2 15:54:29 barbarela kernel: [528230.139678] RBP: ffff8801bdc29d10 R08: ffffea000a1463c0 R09: ffffffffa03fb4af
Oct 2 15:54:29 barbarela kernel: [528230.139695] R10: ffff88028518f500 R11: 0000000040000004 R12: 0000000000000000
Oct 2 15:54:29 barbarela kernel: [528230.139711] R13: ffff88001555bb20 R14: 0000000000000000 R15: ffff8800a86b2180
Oct 2 15:54:29 barbarela kernel: [528230.139730] FS: 00007fc55e013700(0000) GS:ffff88043ec40000(0000) knlGS:0000000000000000
Oct 2 15:54:29 barbarela kernel: [528230.140874] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Oct 2 15:54:29 barbarela kernel: [528230.142016] CR2: 0000000000000010 CR3: 000000038bac3000 CR4: 00000000000406e0
Oct 2 15:54:29 barbarela kernel: [528230.142956] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Oct 2 15:54:29 barbarela kernel: [528230.142956] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 00000000...

[Sergio Gelato (sergio-gelato)]

* ScHRiLL [2014-10-02 14:01:59 +0000]:
> Same error with new kernel. It was fine and working without a hick up
> and today the same issue reverted. 16:01:16 up 6 days

Please check changelog.Debian.gz before jumping to conclusions. The fix is
not in #103 because it was committed too late in the cycle. Enable
precise-proposed, install 70.105 and try again.

> Using
> 3.2.0-69-generic #103-Ubuntu SMP Tue Sep 2 05:02:14 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

[ScHRiLL (gorjan)]

I'm sorry, I've read that it didn't got into 68 and concluded it would be in 69. Will check now, tnx a bunch...

[Brad Figg (brad-figg)]

This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed-precise' to 'verification-done-precise'.

If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you!

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.13.0-37.64

---------------
linux (3.13.0-37.64) trusty; urgency=low

  [ Joseph Salisbury ]

  * Release Tracking Bug
    - LP: #1372576

  [ dann frazier ]

  * [Config] CONFIG_HW_RANDOM_XGENE=m on arm64

  [ Edward Lin ]

  * SAUCE: Add use_native_backlight quirk for Dell Inspiron 5721/3521
    - LP: #1354253, #1354313

  [ Tim Gardner ]

  * SAUCE: Fix nfs oops stable regression
    - LP: #1348670
  * [Config] Add mpt3sas to d-i
    - LP: #1368907
  * [Config] CONFIG_X86_16BIT=y
    - LP: #1371601

  [ Timo Aaltonen ]

  * SAUCE: i915_bdw: Rebase to v3.15.8
    - LP: #1359213

  [ Upstream Kernel Changes ]

  * Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime
    option"
    - LP: #1371601
  * mmc: rtsx: add R1-no-CRC mmc command type handle
    - LP: #1365378
  * rpc_pipe: remove the clntXX dir if creating the pipe fails
    - LP: #1365869
  * sunrpc: add an "info" file for the dummy gssd pipe
    - LP: #1365869
  * rpc_pipe: fix cleanup of dummy gssd directory when notification fails
    - LP: #1365869
  * hwrng: xgene - add support for APM X-Gene SoC RNG support
    - LP: #1365593
  * Documentation: rng: Add X-Gene SoC RNG driver documentation
    - LP: #1365593
  * arm64: dts: add random number generator dts node to APM X-Gene
    platform.
    - LP: #1365593
  * xen/balloon: cancel ballooning if adding new memory failed
    - LP: #1304001
  * x86/xen: resume timer irqs early
    - LP: #1368724
  * xen/manage: Always freeze/thaw processes when suspend/resuming
    - LP: #1368724
  * scsi_transport_sas: move bsg destructor into sas_rphy_remove
    - LP: #1368991
  * drm/i915: Enable 5.4Ghz (HBR2) link rate for Displayport 1.2-capable
    devices
    - LP: #1369633
  * bnx2x: Fix link for KR with swapped polarity lane
    - LP: #1370716
  * drm: add DRM_CAPs for cursor size
    - LP: #1359213
  * drm/dp: Add AUX channel infrastructure
    - LP: #1359213
  * drm/dp: Add drm_dp_dpcd_read_link_status()
    - LP: #1359213
  * drm/dp: Add DisplayPort link helpers
    - LP: #1359213
  * drm/dp: Allow registering AUX channels as I2C busses
    - LP: #1359213
  * drm/dp: let drivers specify the name of the I2C-over-AUX adapter
    - LP: #1359213
  * drm/dp: make aux retries less chatty
    - LP: #1359213
  * Bluetooth: Enable Atheros 0cf3:311e for firmware upload
    - LP: #1371477
  * bnx2x: fix crash during TSO tunneling
    - LP: #1371601
  * inetpeer: get rid of ip_id_count
    - LP: #1371601
  * ip: make IP identifiers less predictable
    - LP: #1371601
  * tcp: Fix integer-overflows in TCP veno
    - LP: #1371601
  * tcp: Fix integer-overflow in TCP vegas
    - LP: #1371601
  * macvlan: Initialize vlan_features to turn on offload support.
    - LP: #1371601
  * net: Correctly set segment mac_len in skb_segment().
    - LP: #1371601
  * iovec: make sure the caller actually wants anything in
    memcpy_fromiovecend
    - LP: #1371601
  * batman-adv: Fix out-of-order fragmentation support
    - LP: #1371601
  * sctp: fix possible seqlock seadlock in sctp_packet_transmit()
    - LP: #1371601
  * sparc64: Fix argument sign extension for compat_sys_futex().
    - LP: #1371601
  ...

[Launchpad Janitor (janitor)]

This bug was fixed in the package linux - 3.2.0-70.105

---------------
linux (3.2.0-70.105) precise; urgency=low

  [ Kamal Mostafa ]

  * Release Tracking Bug
    - re-used previous tracking bug

  [ Upstream Kernel Changes ]

  * udf: Avoid infinite loop when processing indirect ICBs
    - LP: #1370042
    - CVE-2014-6410

linux (3.2.0-70.104) precise; urgency=low

  [ Joseph Salisbury ]

  * Release Tracking Bug
    - LP: #1372522

  [ Tim Gardner ]

  * SAUCE: Fix nfs oops stable regression
    - LP: #1348670
  * [Config] updateconfigs
    - LP: #1369711

  [ Upstream Kernel Changes ]

  * Revert "x86-64, modify_ldt: Make support for 16-bit segments a runtime
    option"
    - LP: #1369711
  * KVM: x86: Inter-privilege level ret emulation is not implemeneted
    - LP: #1369711
  * ASoC: samsung: Correct I2S DAI suspend/resume ops
    - LP: #1369711
  * block: don't assume last put of shared tags is for the host
    - LP: #1369711
  * stable_kernel_rules: Add pointer to netdev-FAQ for network patches
    - LP: #1369711
  * debugfs: Fix corrupted loop in debugfs_remove_recursive
    - LP: #1369711
  * serial: core: Preserve termios c_cflag for console resume
    - LP: #1369711
  * tda10071: force modulation to QPSK on DVB-S
    - LP: #1369711
  * gspca_pac7302: Add new usb-id for Genius i-Look 317
    - LP: #1369711
  * mtd/ftl: fix the double free of the buffers allocated in build_maps()
    - LP: #1369711
  * x86: don't exclude low BIOS area when allocating address space for
    non-PCI cards
    - LP: #1369711
  * Bluetooth: never linger on process exit
    - LP: #1369711
  * scsi: handle flush errors properly
    - LP: #1369711
  * USB: OHCI: don't lose track of EDs when a controller dies
    - LP: #1369711
  * ahci: add support for the Promise FastTrak TX8660 SATA HBA (ahci mode)
    - LP: #1369711
  * usbcore: don't log on consecutive debounce failures of the same port
    - LP: #1369711
  * USB: Fix persist resume of some SS USB devices
    - LP: #1369711
  * drm/radeon: fix irq ring buffer overflow handling
    - LP: #1369711
  * hwmon: (smsc47m192) Fix temperature limit and vrm write operations
    - LP: #1369711
  * staging: vt6655: Fix Warning on boot handle_irq_event_percpu.
    - LP: #1369711
  * staging: vt6655: Fix disassociated messages every 10 seconds
    - LP: #1369711
  * bfa: Fix undefined bit shift on big-endian architectures with 32-bit
    DMA address
    - LP: #1369711
  * hpsa: fix bad -ENOMEM return value in hpsa_big_passthru_ioctl
    - LP: #1369711
  * Drivers: scsi: storvsc: Implement a eh_timed_out handler
    - LP: #1369711
  * Fix gcc-4.9.0 miscompilation of load_balance() in scheduler
    - LP: #1369711
  * iommu/vt-d: Exclude devices using RMRRs from IOMMU API domains
    - LP: #1369711
  * net: sendmsg: fix NULL pointer dereference
    - LP: #1369711
  * tpm: Provide a generic means to override the chip returned timeouts
    - LP: #1369711
  * hwmon: (ads1015) Fix off-by-one for valid channel index checking
    - LP: #1369711
  * MIPS: tlbex: Fix a missing statement for HUGETLB
    - LP: #1369711
  * MIPS: Prevent user from setting FCSR cause bits
    - LP: #1369711
  * mm, thp: do not allow thp faults t...

[Frank (frank-scriptzone)]

Issue seems to be reintroduced.

Mounts in 3.13.0-66-generic fail again with the same error messages as reported in this issue.
In 3.13.0-62-generic everything seems well.

[Sergio Gelato (sergio-gelato)]

Frank: I think it's better to file a new bug about this. Do include the actual log message. I'm looking at the source code for 3.13.0-66.108 and the fix is still in place, so it can't be *exactly* the same problem as before.