Debian Bug report logs - #886329
First access to aufs union mount with Linux 4.14+ triggers kernel BUG at /root/aufs4-standalone/fs/aufs/finfo.c:113

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: intrigeri@debian.org

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Thu, 04 Jan 2018 15:13:03 +0100

Package: aufs-dkms
Version: 4.14+20171218-1
Severity: important
User: tails-dev@boum.org
Usertags: misc-reported
X-Debbugs-Cc: anonym@riseup.net

Hi,

this bug makes aufs unusable in the context of Tails with Linux 4.14,
and possibly with any other Debian Live or container system that still
uses aufs. Initially I've identified it because it prevents Tails ISO
images with Linux 4.14 from booting, but I've reproduced it on regular
Debian systems:  current sid (Linux 4.14.7-1) and Stretch (Linux
4.14.7-1~bpo9+1), in both cases with aufs-dkms 4.14+20171218-1.

Does aufs work for you with different settings?
If yes, let's stick to Severity: important… and I'm curious what
settings you're using. If not, then let's make this RC.

Here's how to reproduce:

  # modprobe aufs debug=1 \
    && mkdir /tmp/{ro,rw,mount} \
    && touch /tmp/ro/bla \
    && mount -t aufs -o dirs=/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount

⇒ so far, so good.

But then:

  # ls /tmp/mount
  Segmentation fault

Here's what I see in my kernel log:

  aufs dump_opts:577:mount[1184]: DEBUG: add {b0, /tmp/rw, 0x1, ffff912c3b916b40}
  aufs dump_opts:577:mount[1184]: DEBUG: add {b1, /tmp/ro, 0x1004, ffff912c3b916240}
  aufs au_xino_def:1278:mount[1184]: DEBUG: /tmp/rw/.aufs.xino
  aufs h_d_revalidate:890:ls[1185]: DEBUG: b0, rw
  aufs h_d_revalidate:890:ls[1185]: DEBUG: b1, ro
  aufs h_d_revalidate:890:ls[1185]: DEBUG: b0, rw
  aufs h_d_revalidate:890:ls[1185]: DEBUG: b1, ro
  aufs aufs_iterate_shared:479:ls[1185]: DEBUG: /, ctx{filldir, 0}
  aufs vfsub_iterate_dir:588:ls[1185]: DEBUG: rw, ctx{fillvdir [aufs], 0}
  aufs au_nhash_append_wh:251:ls[1185]: DEBUG: .wh.orph
  aufs au_nhash_append_wh:251:ls[1185]: DEBUG: .wh.aufs
  aufs au_xino_new_ino:695:ls[1185]: DEBUG: i11
  aufs au_nhash_append_wh:251:ls[1185]: DEBUG: .wh.plnk
  aufs vfsub_iterate_dir:588:ls[1185]: DEBUG: rw, ctx{fillvdir [aufs], 9223372036854775807}
  aufs vfsub_iterate_dir:588:ls[1185]: DEBUG: ro, ctx{fillvdir [aufs], 9223372036854775807}
  aufs test_known:225:ls[1185]: DEBUG: .
  aufs test_known:225:ls[1185]: DEBUG: ..
  aufs au_xino_new_ino:695:ls[1185]: DEBUG: i12
  aufs vfsub_iterate_dir:588:ls[1185]: DEBUG: ro, ctx{fillvdir [aufs], 9223372036854775807}
  aufs seek_vdir:805:ls[1185]: DEBUG: offset 0
  aufs au_vdir_fill_de:867:ls[1185]: DEBUG: ., off0, i2, dt4
  aufs au_vdir_fill_de:867:ls[1185]: DEBUG: .., off16, i11, dt4
  aufs au_vdir_fill_de:867:ls[1185]: DEBUG: bla, off32, i12, dt8
  aufs aufs_iterate_shared:479:ls[1185]: DEBUG: /, ctx{filldir, 48}
  aufs seek_vdir:805:ls[1185]: DEBUG: offset 48
  ------------[ cut here ]------------
  kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113!
  invalid opcode: 0000 [#1] SMP
  Modules linked in: aufs(O) iscsi_target_mod target_core_mod uinput ebtable_filter ebtables ip6table_filter ip6_tables iptable_filter configfs devlink snd_hda_codec_generic kvm_intel snd_hda_intel kvm snd_hda_codec irqbypass snd_hda_core snd_hwdep snd_pcm joydev snd_timer pcspkr virtio_input virtio_balloon snd serio_raw virtio_console soundcore sg evdev parport_pc ppdev lp parport ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 crc32c_generic fscrypto ecb algif_skcipher af_alg dm_crypt dm_mod sr_mod cdrom ata_generic virtio_gpu ttm drm_kms_helper drm virtio_blk crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pcbc 8139too aesni_intel aes_x86_64 crypto_simd glue_helper cryptd psmouse ahci ata_piix libahci i2c_piix4 virtio_pci uhci_hcd virtio_ring libata virtio ehci_hcd
   scsi_mod usbcore 8139cp mii usb_common floppy button
  CPU: 3 PID: 1185 Comm: ls Tainted: G           O    4.14.0-2-amd64 #1 Debian 4.14.7-1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
  task: ffff912c3a0370c0 task.stack: ffffa7f380650000
  RIP: 0010:au_finfo_fin+0x5b/0x60 [aufs]
  RSP: 0018:ffffa7f380653e30 EFLAGS: 00010202
  RAX: 0000000000000001 RBX: ffff912c3a72cd00 RCX: 0000000000000020
  RDX: ffffffffffffffe0 RSI: ffff912c3a8cf480 RDI: ffff912c380e7070
  RBP: ffffa7f380653e38 R08: 0000000000000000 R09: 0000000000000000
  R10: ffff912c3af98618 R11: ffff912c3a72cd10 R12: ffff912c388e01f0
  R13: ffff912c3a8cf480 R14: ffff912c388e01c0 R15: ffff912c3a72cd00
  FS:  00007fb25920b040(0000) GS:ffff912c3fd80000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 000055699add88c8 CR3: 0000000079cee005 CR4: 00000000001606e0
  Call Trace:
   aufs_release_dir+0x101/0x130 [aufs]
   __fput+0xe7/0x220
   ____fput+0xe/0x10
   task_work_run+0x97/0xc0
   exit_to_usermode_loop+0xc0/0xd0
   do_syscall_64+0x119/0x120
   entry_SYSCALL64_slow_path+0x25/0x25
  RIP: 0033:0x7fb258af2747
  RSP: 002b:00007ffc8046c300 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
  RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007fb258af2747
  RDX: 0000000000012740 RSI: 0000000000000000 RDI: 0000000000000003
  RBP: 0000000000000000 R08: 0000000000000000 R09: 000055699add0905
  R10: 000000000000016c R11: 0000000000000202 R12: 00007fb25920aed8
  R13: 000055699add0890 R14: 000055699add0870 R15: 0000000000000000
  Code: 76 e4 48 8b b3 c8 00 00 00 48 83 7e 50 00 75 19 8b 05 b2 eb 06 e5 85 c0 75 11 48 8b 3d 5f 98 02 00 e8 ca 53 5d e4 5b 5d c3 0f 0b <0f> 0b 0f 1f 00 0f 1f 44 00 00 55 48 83 c7 08 48 c7 c2 38 30 66 
  RIP: au_finfo_fin+0x5b/0x60 [aufs] RSP: ffffa7f380653e30
  ---[ end trace dfbfefac21f1ff7d ]---

Let me know if there's additional info I should provide to enable
efficient debugging of this problem.

-- System Information:
Debian Release: buster/sid
  APT prefers unstable
  APT policy: (990, 'unstable'), (500, 'stable-updates'), (500, 'oldstable-updates'), (500, 'testing'), (500, 'stable'), (500, 'oldstable'), (1, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.14.0-2-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages aufs-dkms depends on:
ii  dkms               2.3-3
ii  linux-kbuild-4.14  4.14.7-1

Versions of packages aufs-dkms recommends:
ii  aufs-tools  1:4.9+20170918-1

Versions of packages aufs-dkms suggests:
pn  aufs-dev  <none>

-- no debconf information

-- 
intrigeri

Message #10 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: 886329@bugs.debian.org

Cc: anonym@riseup.net

Subject: Re: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Thu, 04 Jan 2018 15:42:56 +0100

Hi,

interestingly, only the first access to the aufs mountpoint triggers
the bug. See the first `ls' failing and the second one working:

  # modprobe aufs debug=1 \
    && mkdir /tmp/{ro,rw,mount} \
    && touch /tmp/ro/bla \
    && mount -t aufs -o dirs =/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount \
    && ls /tmp/mount ; \
    ls /tmp/mount
  Segmentation fault
  bla

I've tested replacing that first read access with a write access,
same result.

(Off-topic: I'll try to implement a workaround in live-boot.)

Cheers,
-- 
intrigeri

Message #15 received at 886329@bugs.debian.org (full text, mbox, reply):

From: Jan Luca Naumann <j.naumann@fu-berlin.de>

To: intrigeri <intrigeri@debian.org>,886329@bugs.debian.org

Cc: anonym@riseup.net

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Fri, 05 Jan 2018 09:34:33 +0100

Hey,

I am not at home for another two days and do not have a proper computer with me. I will take a look at the problem on the weekend.

Jan

Am 4. Januar 2018 15:42:56 MEZ schrieb intrigeri <intrigeri@debian.org>:
>Hi,
>
>interestingly, only the first access to the aufs mountpoint triggers
>the bug. See the first `ls' failing and the second one working:
>
>  # modprobe aufs debug=1 \
>    && mkdir /tmp/{ro,rw,mount} \
>    && touch /tmp/ro/bla \
>   && mount -t aufs -o dirs =/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount \
>    && ls /tmp/mount ; \
>    ls /tmp/mount
>  Segmentation fault
>  bla
>
>I've tested replacing that first read access with a write access,
>same result.
>
>(Off-topic: I'll try to implement a workaround in live-boot.)
>
>Cheers,

Message #20 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: 886329@bugs.debian.org

Cc: anonym@riseup.net

Subject: Re: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Fri, 05 Jan 2018 09:57:05 +0100

Hi,

in case it might help other Live systems still using aufs for some
reason, for the record I've implemented a workaround to this bug in
Tails:

  https://git-tails.immerda.ch/tails/tree/config/chroot_local-patches/live-boot:_workaround_aufs_bug.patch?h=feature/14976-linux-4.14%2bforce-all-tests

(the only downside I've noticed so far is that the Plymouth splash
screen disappears as soon as the bug is triggered, and the boot
messages display is corrupted by the kernel bug message and call
trace)

Cheers!

Message #25 received at 886329@bugs.debian.org (full text, mbox, reply):

From: Jan Luca Naumann <j.naumann@fu-berlin.de>

To: intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org

Cc: anonym@riseup.net

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Mon, 22 Jan 2018 22:02:53 +0100

Control: tags -1 unreproducible

Hey,

sorry for the long delay for my answer.

I tested your code sample below and I could not reproduce the bug with a
current 4.14.13 kernel on my system. Could you please test it again?

Best regards,
Jan

Am 04.01.2018 um 15:42 schrieb intrigeri:
> Hi,
> 
> interestingly, only the first access to the aufs mountpoint triggers
> the bug. See the first `ls' failing and the second one working:
> 
>   # modprobe aufs debug=1 \
>     && mkdir /tmp/{ro,rw,mount} \
>     && touch /tmp/ro/bla \
>     && mount -t aufs -o dirs =/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount \
>     && ls /tmp/mount ; \
>     ls /tmp/mount
>   Segmentation fault
>   bla
> 
> I've tested replacing that first read access with a write access,
> same result.
> 
> (Off-topic: I'll try to implement a workaround in live-boot.)
> 
> Cheers,
> 

Message #32 received at 886329@bugs.debian.org (full text, mbox, reply):

From: anonym <anonym@riseup.net>

To: Jan Luca Naumann <j.naumann@fu-berlin.de>, intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Mon, 22 Jan 2018 21:12:00 +0000

Jan Luca Naumann:
> Control: tags -1 unreproducible
> 
> I tested your code sample below and I could not reproduce the bug with a
> current 4.14.13 kernel on my system. Could you please test it again?

I am not the reporter, but this bug still affects me using linux-image-4.14.0-3-amd64 4.14.13-1.

Cheers!

Message #37 received at 886329@bugs.debian.org (full text, mbox, reply):

From: anonym <anonym@riseup.net>

To: Jan Luca Naumann <j.naumann@fu-berlin.de>, intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Mon, 22 Jan 2018 22:40:00 +0000

anonym:
> Jan Luca Naumann:
>> Control: tags -1 unreproducible
>>
>> I tested your code sample below and I could not reproduce the bug with a
>> current 4.14.13 kernel on my system. Could you please test it again?
> 
> I am not the reporter, but this bug still affects me using linux-image-4.14.0-3-amd64 4.14.13-1.

I guess that you, Jan, are *not* mounting a tmpfs on /tmp and I am guessing that you, intrigeri, *are*. Am I correct? :) At least for me, the segfault only triggers when the underlying fs is a tmpfs.

Cheers!

Message #42 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: anonym <anonym@riseup.net>

Cc: Jan Luca Naumann <j.naumann@fu-berlin.de>, 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Tue, 23 Jan 2018 12:44:53 +0100

anonym:
> I guess that you, Jan, are *not* mounting a tmpfs on /tmp and I am guessing that you,
> intrigeri, *are*. Am I correct? :)

I am indeed. Jan, can you reproduce if the underlying filesystem is tmpfs?

> At least for me, the segfault only triggers when the underlying fs
> is a tmpfs.

That may be exactly the info Jan needs to forward this upstream.

Cheers!
-- 
intrigeri

Message #47 received at 886329@bugs.debian.org (full text, mbox, reply):

From: Jan Luca Naumann <j.naumann@fu-berlin.de>

To: intrigeri <intrigeri@debian.org>, anonym <anonym@riseup.net>

Cc: 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Tue, 23 Jan 2018 21:58:02 +0100

Hey,

the underlying filesystem is a tmpfs for me as well:

# uname -a
Linux 4.14.0-3-amd64 #1 SMP Debian 4.14.13-1 (2018-01-14) x86_64

# mount | grep /tmp
none on /tmp type tmpfs (rw,nosuid,nodev,noatime,nodiratime)

# modprobe aufs debug=1 \
  && mkdir /tmp/{ro,rw,mount} \
  && touch /tmp/ro/bla \
  && mount -t aufs -o dirs=/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount \
  && ls /tmp/mount ; \
     ls /tmp/mount
bla
bla

I get no segfault for the call still so there has to be another reason...

Best regards,
Jan

Am 23.01.2018 um 12:44 schrieb intrigeri:
> anonym:
>> I guess that you, Jan, are *not* mounting a tmpfs on /tmp and I am guessing that you,
>> intrigeri, *are*. Am I correct? :)
> 
> I am indeed. Jan, can you reproduce if the underlying filesystem is tmpfs?
> 
>> At least for me, the segfault only triggers when the underlying fs
>> is a tmpfs.
> 
> That may be exactly the info Jan needs to forward this upstream.
> 
> Cheers!
> 

Message #52 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: Jan Luca Naumann <j.naumann@fu-berlin.de>

Cc: anonym <anonym@riseup.net>, 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Wed, 24 Jan 2018 09:50:37 +0100

Jan Luca Naumann:
> the underlying filesystem is a tmpfs for me as well:
> [...]
> I get no segfault for the call still so there has to be another reason...

Indeed!

I've just reproduced this in an up-to-date sid VM where /tmp is on the
ext4 root filesystem. I've purged and reinstalled aufs-dkms to make
sure I had a fresh copy built with the current compiler etc. from sid.
I've also tried with AppArmor disabled, same result.

anonym can reproduce it too, and the bug can be reproduced
consistently while booting Tails 3.5 (for testing purposes, one can
grab the ISO from
http://dl.amnesia.boum.org/tails/stable/tails-amd64-3.5/ and boot it
in a VM).

Perhaps we should take it upstream and hope the debug trace will ring
a bell for them?

Cheers,
-- 
intrigeri

Message #57 received at 886329@bugs.debian.org (full text, mbox, reply):

From: Jan Luca Naumann <j.naumann@fu-berlin.de>

To: intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org

Cc: anonym <anonym@riseup.net>

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Wed, 24 Jan 2018 10:11:55 +0100

Hey,

could you please provide the additional information the upstream
developer requests for in the README, then I will forward it to upstream:

5. Contact
----------------------------------------
When you have any problems or strange behaviour in aufs, please let me
know with:
- /proc/mounts (instead of the output of mount(8))
- /sys/module/aufs/*
- /sys/fs/aufs/* (if you have them)
- /debug/aufs/* (if you have them)
- linux kernel version
  if your kernel is not plain, for example modified by distributor,
  the url where i can download its source is necessary too.
- aufs version which was printed at loading the module or booting the
  system, instead of the date you downloaded.
- configuration (define/undefine CONFIG_AUFS_xxx)
- kernel configuration or /proc/config.gz (if you have it)
- behaviour which you think to be incorrect
- actual operation, reproducible one is better
- mailto: aufs-users at lists.sourceforge.net

Best regards,
Jan

Am 24.01.2018 um 09:50 schrieb intrigeri:
> Indeed!
> 
> I've just reproduced this in an up-to-date sid VM where /tmp is on
> the ext4 root filesystem. I've purged and reinstalled aufs-dkms to
> make sure I had a fresh copy built with the current compiler etc.
> from sid. I've also tried with AppArmor disabled, same result.
> 
> anonym can reproduce it too, and the bug can be reproduced 
> consistently while booting Tails 3.5 (for testing purposes, one
> can grab the ISO from 
> http://dl.amnesia.boum.org/tails/stable/tails-amd64-3.5/ and boot
> it in a VM).
> 
> Perhaps we should take it upstream and hope the debug trace will
> ring a bell for them?

Message #62 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: 886329@bugs.debian.org

Cc: anonym <anonym@riseup.net>

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Mon, 19 Feb 2018 08:49:53 +0100

[Message part 1 (text/plain, inline)]

Hi,

Jan Luca Naumann:
> could you please provide the additional information the upstream
> developer requests for in the README, then I will forward it to upstream:

Sure!

To make communication with upstream easier I've retried with Linux
4.15.0-1 and manually compiled aufs4.15 20180219 in an up-to-date and
mostly clean sid VM.

This bug appeared after upgrading from Linux 4.13 to Linux 4.14.

> When you have any problems or strange behaviour in aufs, please let me
> know with:
> - /proc/mounts (instead of the output of mount(8))

# cat /proc/mounts 
sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
udev /dev devtmpfs rw,nosuid,relatime,size=1005588k,nr_inodes=251397,mode=755 0 0
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
tmpfs /run tmpfs rw,nosuid,noexec,relatime,size=204484k,mode=755 0 0
/dev/mapper/sid--desktop--vg-root / ext4 rw,relatime,errors=remount-ro,data=ordered 0 0
securityfs /sys/kernel/security securityfs rw,nosuid,nodev,noexec,relatime 0 0
tmpfs /dev/shm tmpfs rw,nosuid,nodev 0 0
tmpfs /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0
tmpfs /sys/fs/cgroup tmpfs ro,nosuid,nodev,noexec,mode=755 0 0
cgroup /sys/fs/cgroup/unified cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0
cgroup /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,xattr,name=systemd 0 0
pstore /sys/fs/pstore pstore rw,nosuid,nodev,noexec,relatime 0 0
cgroup /sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0
cgroup /sys/fs/cgroup/memory cgroup rw,nosuid,nodev,noexec,relatime,memory 0 0
cgroup /sys/fs/cgroup/net_cls,net_prio cgroup rw,nosuid,nodev,noexec,relatime,net_cls,net_prio 0 0
cgroup /sys/fs/cgroup/perf_event cgroup rw,nosuid,nodev,noexec,relatime,perf_event 0 0
cgroup /sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0
cgroup /sys/fs/cgroup/devices cgroup rw,nosuid,nodev,noexec,relatime,devices 0 0
cgroup /sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0
cgroup /sys/fs/cgroup/cpu,cpuacct cgroup rw,nosuid,nodev,noexec,relatime,cpu,cpuacct 0 0
cgroup /sys/fs/cgroup/pids cgroup rw,nosuid,nodev,noexec,relatime,pids 0 0
systemd-1 /proc/sys/fs/binfmt_misc autofs rw,relatime,fd=27,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=12446 0 0
debugfs /sys/kernel/debug debugfs rw,relatime 0 0
mqueue /dev/mqueue mqueue rw,relatime 0 0
hugetlbfs /dev/hugepages hugetlbfs rw,relatime,pagesize=2M 0 0
/dev/vda1 /boot ext2 rw,relatime,block_validity,barrier,user_xattr,acl 0 0
tmpfs /run/user/116 tmpfs rw,nosuid,nodev,relatime,size=204480k,mode=700,uid=116,gid=120 0 0
configfs /sys/kernel/config configfs rw,relatime 0 0
tmpfs /run/user/0 tmpfs rw,nosuid,nodev,relatime,size=204480k,mode=700 0 0
aufs /tmp/mount aufs rw,relatime,si=df346fccc2a2e857 0 0

> - /sys/module/aufs/*

Not sure what exactly I should extract from this directory so let's
try that:

# for param in /sys/module/aufs/parameters/* ; do echo " - $(basename $param): $(cat $param)"; done 
 - allow_userns: N
 - brs: 1
 - debug: 1

# for f in $(find /sys/module/aufs -maxdepth 1 -type f); do echo " - $(basename $f): $(cat $f)" ; done
 - version: 4.15-20180219
 - taint: O
 - initsize: 0
 - initstate: live
 - srcversion: 4AEC6984C511AF142683949
 - coresize: 376832
 - refcnt: 2
cat: /sys/module/aufs/uevent: Permission denied
 - uevent: 

> - /sys/fs/aufs/* (if you have them)

# cat /sys/fs/aufs/config 
CONFIG_AUFS_FS=m
CONFIG_AUFS_BRANCH_MAX_127=y
CONFIG_AUFS_SBILIST=y
CONFIG_AUFS_DEBUG=y

# for f in /sys/fs/aufs/*/*; do echo " - $(basename $f): $(cat $f)" ; done
 - br0: /tmp/rw=rw
 - br1: /tmp/ro=rr+wh
 - brid0: 64
 - brid1: 65
 - xi_path: /tmp/rw/.aufs.xino

> - /debug/aufs/* (if you have them)

I have no /debug.

> - linux kernel version
>   if your kernel is not plain, for example modified by distributor,
>   the url where i can download its source is necessary too.

Debian sid's linux-image-4.15.0-1-amd64, version 4.15.4-1.
Patched source: http://ftp.us.debian.org/debian/pool/main/l/linux/linux-source-4.15_4.15.4-1_all.deb
that is
http://http.debian.net/debian/pool/main/l/linux/linux_4.15.4.orig.tar.xz
+ patches from http://http.debian.net/debian/pool/main/l/linux/linux_4.15.4.orig.tar.xz

> - aufs version which was printed at loading the module or booting the
>   system, instead of the date you downloaded.

aufs 4.15-20180219

> - configuration (define/undefine CONFIG_AUFS_xxx)

I did not change the defaults from
https://github.com/sfjro/aufs4-standalone.git
(branch aufs4.15) before compiling.

> - kernel configuration or /proc/config.gz (if you have it)

Attached.

> - behaviour which you think to be incorrect
> - actual operation, reproducible one is better

The first access to my aufs mountpoint segfaults but the second
access works fine:

  # modprobe aufs debug=1 \
    && mkdir /tmp/{ro,rw,mount} \
    && touch /tmp/ro/bla \
    && mount -t aufs -o dirs =/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount \
    && ls /tmp/mount ; \
    ls /tmp/mount
  Segmentation fault
  bla

Corresponding kernel logs:

 aufs dump_opts:577:mount[3911]: DEBUG: add {b0, /tmp/rw, 0x1, 00000000761dd532}
 aufs dump_opts:577:mount[3911]: DEBUG: add {b1, /tmp/ro, 0x1004, 00000000ee455003}
 aufs au_xino_def:1329:mount[3911]: DEBUG: /tmp/rw/.aufs.xino
 aufs h_d_revalidate:890:ls[3912]: DEBUG: b0, rw
 aufs h_d_revalidate:890:ls[3912]: DEBUG: b1, ro
 aufs h_d_revalidate:890:ls[3912]: DEBUG: b0, rw
 aufs h_d_revalidate:890:ls[3912]: DEBUG: b1, ro
 aufs aufs_iterate_shared:479:ls[3912]: DEBUG: /, ctx{filldir, 0}
 aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: rw, ctx{fillvdir [aufs], 0}
 aufs au_nhash_append_wh:251:ls[3912]: DEBUG: .wh.orph
 aufs au_nhash_append_wh:251:ls[3912]: DEBUG: .wh.aufs
 aufs au_xino_new_ino:746:ls[3912]: DEBUG: i11
 aufs au_nhash_append_wh:251:ls[3912]: DEBUG: .wh.plnk
 aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: rw, ctx{fillvdir [aufs], 9223372036854775807}
 aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: ro, ctx{fillvdir [aufs], 9223372036854775807}
 aufs test_known:225:ls[3912]: DEBUG: .
 aufs test_known:225:ls[3912]: DEBUG: ..
 aufs au_xino_new_ino:746:ls[3912]: DEBUG: i12
 aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: ro, ctx{fillvdir [aufs], 9223372036854775807}
 aufs seek_vdir:805:ls[3912]: DEBUG: offset 0
 aufs au_vdir_fill_de:867:ls[3912]: DEBUG: ., off0, i2, dt4
 aufs au_vdir_fill_de:867:ls[3912]: DEBUG: .., off16, i11, dt4
 aufs au_vdir_fill_de:867:ls[3912]: DEBUG: bla, off32, i12, dt8
 aufs aufs_iterate_shared:479:ls[3912]: DEBUG: /, ctx{filldir, 48}
 aufs seek_vdir:805:ls[3912]: DEBUG: offset 48
 ------------[ cut here ]------------
 kernel BUG at /root/aufs4-standalone/fs/aufs/finfo.c:113!
 invalid opcode: 0000 [#1] SMP PTI
 Modules linked in: aufs(O) iscsi_target_mod target_core_mod uinput ebtable_filter ebtables ip6table_filter ip6_tables configfs devlink iptable_filter kvm_intel snd_hda_codec_generic kvm irqbypass joydev snd_hda_intel serio_raw pcspkr virtio_balloon snd_hda_codec virtio_console virtio_input snd_hda_core snd_hwdep sg snd_pcm snd_timer snd soundcor
  usbcore scsi_mod usb_common i2c_piix4 floppy button
 CPU: 0 PID: 3912 Comm: ls Tainted: G           O     4.15.0-1-amd64 #1 Debian 4.15.4-1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
 RIP: 0010:au_finfo_fin+0x55/0x60 [aufs]
 RSP: 0018:ffffa5c042a63e68 EFLAGS: 00010202
 RAX: 0000000000000001 RBX: ffff8e3bf8230700 RCX: 0000000000000020
 RDX: ffffffffffffffe0 RSI: ffff8e3bb8b0f900 RDI: ffff8e3bf74d3870
 RBP: ffff8e3bf5aaadf0 R08: 0000000000024b40 R09: ffffffffc0b125a0
 R10: fffff882c1d6aa80 R11: 0000000000000000 R12: ffff8e3bb8b0f900
 R13: ffff8e3bf5aaadc0 R14: ffff8e3bf8230700 R15: 0000000000000001
 FS:  00007f9b333d6040(0000) GS:ffff8e3bffc00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 0000562812de58c8 CR3: 0000000077ea6001 CR4: 00000000001606f0
 Call Trace:
  aufs_release_dir+0x101/0x130 [aufs]
  __fput+0xd8/0x210
  task_work_run+0x8a/0xb0
  exit_to_usermode_loop+0xb9/0xc0
  do_syscall_64+0x127/0x130
  entry_SYSCALL_64_after_hwframe+0x21/0x86
 RIP: 0033:0x7f9b32cbe747
 RSP: 002b:00007ffe6dc0e3d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f9b32cbe747
 RDX: 0000000000012740 RSI: 0000000000000000 RDI: 0000000000000003
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000562812ddd905
 R10: 000000000000016c R11: 0000000000000202 R12: 00007f9b333d5ed8
 R13: 0000562812ddd890 R14: 0000562812ddd870 R15: 0000000000000000
 Code: b2 f3 e8 eb 48 8b b3 c8 00 00 00 48 83 7e 50 00 75 17 8b 05 ee d0 b9 ec 85 c0 75 0f 5b 48 8b 3d 02 6e 03 00 e9 dd ab cf eb 0f 0b <0f> 0b 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 83 c7 08 48 
 RIP: au_finfo_fin+0x55/0x60 [aufs] RSP: ffffa5c042a63e68
 ---[ end trace fec727daa8019dc7 ]---
 aufs h_d_revalidate:890:ls[3913]: DEBUG: b0, rw
 aufs h_d_revalidate:890:ls[3913]: DEBUG: b1, ro
 aufs h_d_revalidate:890:ls[3913]: DEBUG: b0, rw
 aufs h_d_revalidate:890:ls[3913]: DEBUG: b1, ro
 aufs aufs_iterate_shared:479:ls[3913]: DEBUG: /, ctx{filldir, 0}
 aufs seek_vdir:805:ls[3913]: DEBUG: offset 0
 aufs au_vdir_fill_de:867:ls[3913]: DEBUG: ., off0, i2, dt4
 aufs au_vdir_fill_de:867:ls[3913]: DEBUG: .., off16, i11, dt4
 aufs au_vdir_fill_de:867:ls[3913]: DEBUG: bla, off32, i12, dt8
 aufs aufs_iterate_shared:479:ls[3913]: DEBUG: /, ctx{filldir, 48}
 aufs seek_vdir:805:ls[3913]: DEBUG: offset 48


Cheers,
-- 
intrigeri

[config-4.15.0-1-amd64 (text/plain, attachment)]

Message #69 received at 886329@bugs.debian.org (full text, mbox, reply):

From: Jan Luca Naumann <j.naumann@fu-berlin.de>

To: sfjro@users.sourceforge.net

Cc: intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org, 886329-forwarded@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Wed, 21 Feb 2018 10:30:03 +0100

Dear aufs-maintainer,

below a Debian bug reporting a seg fault is attached. A online version
of the bug can be found here:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=886329

I could reproduce the bug using a 4.15 kernel. Could you please take a
look into this?

Thank you very much and best regards,
Jan

Am 19.02.2018 um 08:49 schrieb intrigeri:
> Hi,
> 
> Jan Luca Naumann:
>> could you please provide the additional information the upstream
>> developer requests for in the README, then I will forward it to upstream:
> 
> Sure!
> 
> To make communication with upstream easier I've retried with Linux
> 4.15.0-1 and manually compiled aufs4.15 20180219 in an up-to-date and
> mostly clean sid VM.
> 
> This bug appeared after upgrading from Linux 4.13 to Linux 4.14.
> 
>> When you have any problems or strange behaviour in aufs, please let me
>> know with:
>> - /proc/mounts (instead of the output of mount(8))
> 
> # cat /proc/mounts 
> sysfs /sys sysfs rw,nosuid,nodev,noexec,relatime 0 0
> proc /proc proc rw,nosuid,nodev,noexec,relatime 0 0
> udev /dev devtmpfs rw,nosuid,relatime,size=1005588k,nr_inodes=251397,mode=755 0 0
> devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0
> tmpfs /run tmpfs rw,nosuid,noexec,relatime,size=204484k,mode=755 0 0
> /dev/mapper/sid--desktop--vg-root / ext4 rw,relatime,errors=remount-ro,data=ordered 0 0
> securityfs /sys/kernel/security securityfs rw,nosuid,nodev,noexec,relatime 0 0
> tmpfs /dev/shm tmpfs rw,nosuid,nodev 0 0
> tmpfs /run/lock tmpfs rw,nosuid,nodev,noexec,relatime,size=5120k 0 0
> tmpfs /sys/fs/cgroup tmpfs ro,nosuid,nodev,noexec,mode=755 0 0
> cgroup /sys/fs/cgroup/unified cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0
> cgroup /sys/fs/cgroup/systemd cgroup rw,nosuid,nodev,noexec,relatime,xattr,name=systemd 0 0
> pstore /sys/fs/pstore pstore rw,nosuid,nodev,noexec,relatime 0 0
> cgroup /sys/fs/cgroup/blkio cgroup rw,nosuid,nodev,noexec,relatime,blkio 0 0
> cgroup /sys/fs/cgroup/memory cgroup rw,nosuid,nodev,noexec,relatime,memory 0 0
> cgroup /sys/fs/cgroup/net_cls,net_prio cgroup rw,nosuid,nodev,noexec,relatime,net_cls,net_prio 0 0
> cgroup /sys/fs/cgroup/perf_event cgroup rw,nosuid,nodev,noexec,relatime,perf_event 0 0
> cgroup /sys/fs/cgroup/freezer cgroup rw,nosuid,nodev,noexec,relatime,freezer 0 0
> cgroup /sys/fs/cgroup/devices cgroup rw,nosuid,nodev,noexec,relatime,devices 0 0
> cgroup /sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0
> cgroup /sys/fs/cgroup/cpu,cpuacct cgroup rw,nosuid,nodev,noexec,relatime,cpu,cpuacct 0 0
> cgroup /sys/fs/cgroup/pids cgroup rw,nosuid,nodev,noexec,relatime,pids 0 0
> systemd-1 /proc/sys/fs/binfmt_misc autofs rw,relatime,fd=27,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=12446 0 0
> debugfs /sys/kernel/debug debugfs rw,relatime 0 0
> mqueue /dev/mqueue mqueue rw,relatime 0 0
> hugetlbfs /dev/hugepages hugetlbfs rw,relatime,pagesize=2M 0 0
> /dev/vda1 /boot ext2 rw,relatime,block_validity,barrier,user_xattr,acl 0 0
> tmpfs /run/user/116 tmpfs rw,nosuid,nodev,relatime,size=204480k,mode=700,uid=116,gid=120 0 0
> configfs /sys/kernel/config configfs rw,relatime 0 0
> tmpfs /run/user/0 tmpfs rw,nosuid,nodev,relatime,size=204480k,mode=700 0 0
> aufs /tmp/mount aufs rw,relatime,si=df346fccc2a2e857 0 0
> 
>> - /sys/module/aufs/*
> 
> Not sure what exactly I should extract from this directory so let's
> try that:
> 
> # for param in /sys/module/aufs/parameters/* ; do echo " - $(basename $param): $(cat $param)"; done 
>  - allow_userns: N
>  - brs: 1
>  - debug: 1
> 
> # for f in $(find /sys/module/aufs -maxdepth 1 -type f); do echo " - $(basename $f): $(cat $f)" ; done
>  - version: 4.15-20180219
>  - taint: O
>  - initsize: 0
>  - initstate: live
>  - srcversion: 4AEC6984C511AF142683949
>  - coresize: 376832
>  - refcnt: 2
> cat: /sys/module/aufs/uevent: Permission denied
>  - uevent: 
> 
>> - /sys/fs/aufs/* (if you have them)
> 
> # cat /sys/fs/aufs/config 
> CONFIG_AUFS_FS=m
> CONFIG_AUFS_BRANCH_MAX_127=y
> CONFIG_AUFS_SBILIST=y
> CONFIG_AUFS_DEBUG=y
> 
> # for f in /sys/fs/aufs/*/*; do echo " - $(basename $f): $(cat $f)" ; done
>  - br0: /tmp/rw=rw
>  - br1: /tmp/ro=rr+wh
>  - brid0: 64
>  - brid1: 65
>  - xi_path: /tmp/rw/.aufs.xino
> 
>> - /debug/aufs/* (if you have them)
> 
> I have no /debug.
> 
>> - linux kernel version
>>   if your kernel is not plain, for example modified by distributor,
>>   the url where i can download its source is necessary too.
> 
> Debian sid's linux-image-4.15.0-1-amd64, version 4.15.4-1.
> Patched source: http://ftp.us.debian.org/debian/pool/main/l/linux/linux-source-4.15_4.15.4-1_all.deb
> that is
> http://http.debian.net/debian/pool/main/l/linux/linux_4.15.4.orig.tar.xz
> + patches from http://http.debian.net/debian/pool/main/l/linux/linux_4.15.4.orig.tar.xz
> 
>> - aufs version which was printed at loading the module or booting the
>>   system, instead of the date you downloaded.
> 
> aufs 4.15-20180219
> 
>> - configuration (define/undefine CONFIG_AUFS_xxx)
> 
> I did not change the defaults from
> https://github.com/sfjro/aufs4-standalone.git
> (branch aufs4.15) before compiling.
> 
>> - kernel configuration or /proc/config.gz (if you have it)
> 
> Attached.
> 
>> - behaviour which you think to be incorrect
>> - actual operation, reproducible one is better
> 
> The first access to my aufs mountpoint segfaults but the second
> access works fine:
> 
>   # modprobe aufs debug=1 \
>     && mkdir /tmp/{ro,rw,mount} \
>     && touch /tmp/ro/bla \
>     && mount -t aufs -o dirs =/tmp/rw=rw:/tmp/ro=rr+wh aufs /tmp/mount \
>     && ls /tmp/mount ; \
>     ls /tmp/mount
>   Segmentation fault
>   bla
> 
> Corresponding kernel logs:
> 
>  aufs dump_opts:577:mount[3911]: DEBUG: add {b0, /tmp/rw, 0x1, 00000000761dd532}
>  aufs dump_opts:577:mount[3911]: DEBUG: add {b1, /tmp/ro, 0x1004, 00000000ee455003}
>  aufs au_xino_def:1329:mount[3911]: DEBUG: /tmp/rw/.aufs.xino
>  aufs h_d_revalidate:890:ls[3912]: DEBUG: b0, rw
>  aufs h_d_revalidate:890:ls[3912]: DEBUG: b1, ro
>  aufs h_d_revalidate:890:ls[3912]: DEBUG: b0, rw
>  aufs h_d_revalidate:890:ls[3912]: DEBUG: b1, ro
>  aufs aufs_iterate_shared:479:ls[3912]: DEBUG: /, ctx{filldir, 0}
>  aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: rw, ctx{fillvdir [aufs], 0}
>  aufs au_nhash_append_wh:251:ls[3912]: DEBUG: .wh.orph
>  aufs au_nhash_append_wh:251:ls[3912]: DEBUG: .wh.aufs
>  aufs au_xino_new_ino:746:ls[3912]: DEBUG: i11
>  aufs au_nhash_append_wh:251:ls[3912]: DEBUG: .wh.plnk
>  aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: rw, ctx{fillvdir [aufs], 9223372036854775807}
>  aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: ro, ctx{fillvdir [aufs], 9223372036854775807}
>  aufs test_known:225:ls[3912]: DEBUG: .
>  aufs test_known:225:ls[3912]: DEBUG: ..
>  aufs au_xino_new_ino:746:ls[3912]: DEBUG: i12
>  aufs vfsub_iterate_dir:588:ls[3912]: DEBUG: ro, ctx{fillvdir [aufs], 9223372036854775807}
>  aufs seek_vdir:805:ls[3912]: DEBUG: offset 0
>  aufs au_vdir_fill_de:867:ls[3912]: DEBUG: ., off0, i2, dt4
>  aufs au_vdir_fill_de:867:ls[3912]: DEBUG: .., off16, i11, dt4
>  aufs au_vdir_fill_de:867:ls[3912]: DEBUG: bla, off32, i12, dt8
>  aufs aufs_iterate_shared:479:ls[3912]: DEBUG: /, ctx{filldir, 48}
>  aufs seek_vdir:805:ls[3912]: DEBUG: offset 48
>  ------------[ cut here ]------------
>  kernel BUG at /root/aufs4-standalone/fs/aufs/finfo.c:113!
>  invalid opcode: 0000 [#1] SMP PTI
>  Modules linked in: aufs(O) iscsi_target_mod target_core_mod uinput ebtable_filter ebtables ip6table_filter ip6_tables configfs devlink iptable_filter kvm_intel snd_hda_codec_generic kvm irqbypass joydev snd_hda_intel serio_raw pcspkr virtio_balloon snd_hda_codec virtio_console virtio_input snd_hda_core snd_hwdep sg snd_pcm snd_timer snd soundcor
>   usbcore scsi_mod usb_common i2c_piix4 floppy button
>  CPU: 0 PID: 3912 Comm: ls Tainted: G           O     4.15.0-1-amd64 #1 Debian 4.15.4-1
>  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
>  RIP: 0010:au_finfo_fin+0x55/0x60 [aufs]
>  RSP: 0018:ffffa5c042a63e68 EFLAGS: 00010202
>  RAX: 0000000000000001 RBX: ffff8e3bf8230700 RCX: 0000000000000020
>  RDX: ffffffffffffffe0 RSI: ffff8e3bb8b0f900 RDI: ffff8e3bf74d3870
>  RBP: ffff8e3bf5aaadf0 R08: 0000000000024b40 R09: ffffffffc0b125a0
>  R10: fffff882c1d6aa80 R11: 0000000000000000 R12: ffff8e3bb8b0f900
>  R13: ffff8e3bf5aaadc0 R14: ffff8e3bf8230700 R15: 0000000000000001
>  FS:  00007f9b333d6040(0000) GS:ffff8e3bffc00000(0000) knlGS:0000000000000000
>  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>  CR2: 0000562812de58c8 CR3: 0000000077ea6001 CR4: 00000000001606f0
>  Call Trace:
>   aufs_release_dir+0x101/0x130 [aufs]
>   __fput+0xd8/0x210
>   task_work_run+0x8a/0xb0
>   exit_to_usermode_loop+0xb9/0xc0
>   do_syscall_64+0x127/0x130
>   entry_SYSCALL_64_after_hwframe+0x21/0x86
>  RIP: 0033:0x7f9b32cbe747
>  RSP: 002b:00007ffe6dc0e3d0 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
>  RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f9b32cbe747
>  RDX: 0000000000012740 RSI: 0000000000000000 RDI: 0000000000000003
>  RBP: 0000000000000000 R08: 0000000000000000 R09: 0000562812ddd905
>  R10: 000000000000016c R11: 0000000000000202 R12: 00007f9b333d5ed8
>  R13: 0000562812ddd890 R14: 0000562812ddd870 R15: 0000000000000000
>  Code: b2 f3 e8 eb 48 8b b3 c8 00 00 00 48 83 7e 50 00 75 17 8b 05 ee d0 b9 ec 85 c0 75 0f 5b 48 8b 3d 02 6e 03 00 e9 dd ab cf eb 0f 0b <0f> 0b 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 83 c7 08 48 
>  RIP: au_finfo_fin+0x55/0x60 [aufs] RSP: ffffa5c042a63e68
>  ---[ end trace fec727daa8019dc7 ]---
>  aufs h_d_revalidate:890:ls[3913]: DEBUG: b0, rw
>  aufs h_d_revalidate:890:ls[3913]: DEBUG: b1, ro
>  aufs h_d_revalidate:890:ls[3913]: DEBUG: b0, rw
>  aufs h_d_revalidate:890:ls[3913]: DEBUG: b1, ro
>  aufs aufs_iterate_shared:479:ls[3913]: DEBUG: /, ctx{filldir, 0}
>  aufs seek_vdir:805:ls[3913]: DEBUG: offset 0
>  aufs au_vdir_fill_de:867:ls[3913]: DEBUG: ., off0, i2, dt4
>  aufs au_vdir_fill_de:867:ls[3913]: DEBUG: .., off16, i11, dt4
>  aufs au_vdir_fill_de:867:ls[3913]: DEBUG: bla, off32, i12, dt8
>  aufs aufs_iterate_shared:479:ls[3913]: DEBUG: /, ctx{filldir, 48}
>  aufs seek_vdir:805:ls[3913]: DEBUG: offset 48
> 
> 
> Cheers,
> 
> 
> 
> _______________________________________________
> Filesystems-devel mailing list
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Message #79 received at 886329@bugs.debian.org (full text, mbox, reply):

From: sfjro@users.sourceforge.net

To: Jan Luca Naumann <j.naumann@fu-berlin.de>

Cc: intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org, 886329-forwarded@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Wed, 21 Feb 2018 21:23:45 +0900

Jan Luca Naumann:
> I could reproduce the bug using a 4.15 kernel. Could you please take a
> look into this?

Thanx for the interesting bug report.
Although I could not reproduce the bug, I'm afraid it is an aufs
problem. I will try more and investigate it, but it may take some time.

I am interested in why you set '1' to the aufs module parameter "debug".
If you had not set, this bug would not appear I guess. Did you see
something wrong without setting "debug"? And you tried debugging? If so,
I want to know the original problem too.

Just for the case you are interested in the details:
The line fs/aufs/finfo.c:113 is AuRwDestroy(&finfo->fi_rwsem) which is
an aufs internal debugging macro. It checks the lock-status of the
semaphore by looking up the LOCKDEP info. If the dying semaphore is
still locked, the macro considers it is an unknown bug and produces the
messsage (which you got).
I've searched the bug where fi_rwsem is still locked, but I could not
find. So *currently* I am guessing there is some unmatching between the
LOCKDEP info and the real lock-status.
As you might know, LOCKDEP is a kernel debugging feature and
AuRwDestroy() macro is enabled only when CONFIG_AUFS_DEBUG is
enabled. So I guess if you disabled both of them, you wouldn't meet the
problem.


J. R. Okajima

Message #85 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: sfjro@users.sourceforge.net

Cc: Jan Luca Naumann <j.naumann@fu-berlin.de>, 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Wed, 21 Feb 2018 14:38:07 +0100

sfjro@users.sourceforge.net:
> I am interested in why you set '1' to the aufs module parameter "debug".

IIRC I added it after having noticed the bug, in the hope it would
yield more useful information for developers to fix it.

> If you had not set, this bug would not appear I guess. Did you see
> something wrong without setting "debug"? And you tried debugging? If so,
> I want to know the original problem too.

OK, I'll retry without debug=1.

Thanks!

Cheers,
-- 
intrigeri

Message #90 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: sfjro@users.sourceforge.net

Cc: 886329@bugs.debian.org, Jan Luca Naumann <j.naumann@fu-berlin.de>

Subject: Re: Bug#886329: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Thu, 22 Feb 2018 11:01:19 +0100

intrigeri:
> sfjro@users.sourceforge.net:
>> I am interested in why you set '1' to the aufs module parameter "debug".

> IIRC I added it after having noticed the bug, in the hope it would
> yield more useful information for developers to fix it.

>> If you had not set, this bug would not appear I guess. Did you see
>> something wrong without setting "debug"? And you tried debugging? If so,
>> I want to know the original problem too.

> OK, I'll retry without debug=1.

Same problem without debug=1:

 aufs 4.15-20180219
 ------------[ cut here ]------------
 kernel BUG at /root/aufs4-standalone/fs/aufs/finfo.c:113!
 invalid opcode: 0000 [#1] SMP PTI
 Modules linked in: aufs(O) iscsi_target_mod target_core_mod uinput ebtable_filter ebtables ip6table_filter ip6_tables devlink iptable_filter configfs snd_hda_codec_generic kvm_intel snd_hda_intel kvm snd_hda_codec snd_hda_core irqbypass snd_hwdep snd_pcm joydev snd_timer sg serio_raw pcspkr virtio_console snd virtio_input evdev virtio_balloon soundcore parport_pc ppdev lp parport ip_tables x_tables autofs4 ext4 crc16 mbcache jbd2 crc32c_generic fscrypto ecb algif_skcipher af_alg dm_crypt dm_mod sr_mod cdrom ata_generic virtio_gpu ttm drm_kms_helper drm virtio_blk 8139too crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel pcbc aesni_intel ata_piix ahci aes_x86_64 crypto_simd glue_helper libahci cryptd libata uhci_hcd psmouse i2c_piix4 ehci_hcd 8139cp mii virtio_pci usbcore
  virtio_ring virtio scsi_mod usb_common floppy button
 CPU: 0 PID: 1632 Comm: ls Tainted: G           O     4.15.0-1-amd64 #1 Debian 4.15.4-1
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
 RIP: 0010:au_finfo_fin+0x55/0x60 [aufs]
 RSP: 0018:ffffba4fc07bfe68 EFLAGS: 00010202
 RAX: 0000000000000001 RBX: ffff968df5568600 RCX: 0000000000000020
 RDX: ffffffffffffffe0 RSI: ffff968e00664300 RDI: ffff968e3628c070
 RBP: ffff968e393294b0 R08: 0000000000024b40 R09: ffffffffc0adc5a0
 R10: ffffea6701e4ca40 R11: 0000000000000000 R12: ffff968e00664300
 R13: ffff968e39329480 R14: ffff968df5568600 R15: 0000000000000001
 FS:  00007f1c8e13f040(0000) GS:ffff968e3fc00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00005569e08d08c8 CR3: 0000000076600001 CR4: 00000000001606f0
 Call Trace:
  aufs_release_dir+0x101/0x130 [aufs]
  __fput+0xd8/0x210
  task_work_run+0x8a/0xb0
  exit_to_usermode_loop+0xb9/0xc0
  do_syscall_64+0x127/0x130
  entry_SYSCALL_64_after_hwframe+0x21/0x86
 RIP: 0033:0x7f1c8da27747
 RSP: 002b:00007ffe97932f10 EFLAGS: 00000206 ORIG_RAX: 0000000000000003
 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00007f1c8da27747
 RDX: 0000000000012740 RSI: 0000000000000000 RDI: 0000000000000003
 RBP: 0000000000000000 R08: 0000000000000000 R09: 00005569e08c8905
 R10: 000000000000016c R11: 0000000000000206 R12: 00007f1c8e13eed8
 R13: 00005569e08c8890 R14: 00005569e08c8870 R15: 0000000000000000
 Code: b2 53 6c f3 48 8b b3 c8 00 00 00 48 83 7e 50 00 75 17 8b 05 ee 30 3d f4 85 c0 75 0f 5b 48 8b 3d 02 6e 03 00 e9 dd 0b 53 f3 0f 0b <0f> 0b 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 83 c7 08 48 
 RIP: au_finfo_fin+0x55/0x60 [aufs] RSP: ffffba4fc07bfe68
 ---[ end trace 22dbca8ab81b58bd ]---

# cat /sys/module/aufs/parameters/debug 
0

Cheers,
-- 
intrigeri

Message #95 received at 886329@bugs.debian.org (full text, mbox, reply):

From: sfjro@users.sourceforge.net

To: intrigeri <intrigeri@debian.org>

Cc: 886329@bugs.debian.org, Jan Luca Naumann <j.naumann@fu-berlin.de>

Subject: Re: Bug#886329: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Thu, 22 Feb 2018 19:56:25 +0900

intrigeri:
> Same problem without debug=1:

That is not what I meant.

----------------------------------------------------------------------
As you might know, LOCKDEP is a kernel debugging feature and
AuRwDestroy() macro is enabled only when CONFIG_AUFS_DEBUG is
enabled. So I guess if you disabled both of them, you wouldn't meet the
problem.
----------------------------------------------------------------------

Re-configure and re-compile are necessary, if you want to try.


J. R. Okajima

Message #100 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: sfjro@users.sourceforge.net

Cc: 886329@bugs.debian.org, Jan Luca Naumann <j.naumann@fu-berlin.de>

Subject: Re: Bug#886329: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Thu, 22 Feb 2018 14:09:26 +0100

sfjro@users.sourceforge.net:
> intrigeri:
>> Same problem without debug=1:

> That is not what I meant.

OK, sorry. I got confused by:

   I am interested in why you set '1' to the aufs module parameter "debug".
   If you had not set, this bug would not appear I guess. Did you see
   something wrong without setting "debug"?

… which seemed to refer to that module parameter. Anyway, moving on:

> ----------------------------------------------------------------------
> As you might know, LOCKDEP is a kernel debugging feature and
> AuRwDestroy() macro is enabled only when CONFIG_AUFS_DEBUG is
> enabled. So I guess if you disabled both of them, you wouldn't meet the
> problem.
> ----------------------------------------------------------------------

> Re-configure and re-compile are necessary, if you want to try.

Confirmed! So indeed, this problem only happens when CONFIG_AUFS_DEBUG
is enabled, which is the default setting in aufs4-standalone.git's
config.mk and the Debian aufs-dkms package does not change that.
So let me ask: is it recommended to disable this compilation option
for production use?

Cheers,
-- 
intrigeri

Message #105 received at 886329@bugs.debian.org (full text, mbox, reply):

From: sfjro@users.sourceforge.net

To: intrigeri <intrigeri@debian.org>

Cc: 886329@bugs.debian.org, Jan Luca Naumann <j.naumann@fu-berlin.de>

Subject: Re: Bug#886329: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Fri, 23 Feb 2018 05:31:45 +0900

intrigeri:
> OK, sorry. I got confused by:
>
>    I am interested in why you set '1' to the aufs module parameter "debug".
>    If you had not set, this bug would not appear I guess. Did you see
>    something wrong without setting "debug"?
>
> =E2=80=A6 which seemed to refer to that module parameter. Anyway, moving on:

Ah, that is my bad. Sorry.


> Confirmed! So indeed, this problem only happens when CONFIG_AUFS_DEBUG
> is enabled, which is the default setting in aufs4-standalone.git's
> config.mk and the Debian aufs-dkms package does not change that.
> So let me ask: is it recommended to disable this compilation option
> for production use?

Glad to hear that!
Generally for production use, all debugging feature should be disabled.
The reason I release aufs with CONFIG_AUFS_DEBUG enabled is I secretly
expect a bug report such like this. :-)


J. R. Okajima

Message #110 received at 886329@bugs.debian.org (full text, mbox, reply):

From: sfjro@users.sourceforge.net

To: Jan Luca Naumann <j.naumann@fu-berlin.de>, intrigeri <intrigeri@debian.org>, 886329@bugs.debian.org, 886329-forwarded@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Fri, 23 Feb 2018 06:50:12 +0900

sfjro@users.sourceforge.net:
> Thanx for the interesting bug report.
> Although I could not reproduce the bug, I'm afraid it is an aufs
> problem. I will try more and investigate it, but it may take some time.

On the report, I can see that you use aufs in qemu.
Would you kindly tell me how you invoked it? I mean the exact command
line. Because I cannot reproduce the problem on my test machine, intel
core2duo (I know this is old machine). Do you have more cpu cores? Do
you think that more and more cores get more chances to reproduce?


J. R. Okajima

Message #116 received at 886329-close@bugs.debian.org (full text, mbox, reply):

From: Jan Luca Naumann <j.naumann@fu-berlin.de>

To: 886329-close@bugs.debian.org

Subject: Bug#886329: fixed in aufs 4.15+20180219-1

Date: Sat, 24 Feb 2018 14:50:06 +0000

Source: aufs
Source-Version: 4.15+20180219-1

We believe that the bug you reported is fixed in the latest version of
aufs, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 886329@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Jan Luca Naumann <j.naumann@fu-berlin.de> (supplier of updated aufs package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)


-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

Format: 1.8
Date: Sat, 24 Feb 2018 14:08:39 +0100
Source: aufs
Binary: aufs-dkms aufs-dev
Architecture: source
Version: 4.15+20180219-1
Distribution: unstable
Urgency: medium
Maintainer: Filesystems Group <filesystems-devel@lists.alioth.debian.org>
Changed-By: Jan Luca Naumann <j.naumann@fu-berlin.de>
Description:
 aufs-dev   - Development files for aufs
 aufs-dkms  - DKMS files to build and install aufs
Closes: 884008 886329
Changes:
 aufs (4.15+20180219-1) unstable; urgency=medium
 .
   * New upstream release.
     - Remove a warning about the internal file-close. (Closes: #884008)
   * debian/patches:
     - Disable CONFIG_AUFS_DEBUG in config.mk. (Closes: #886329)
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 2ba21e5534ab91ace5dffd568a8b5bb663fb0aab 239797 aufs_4.15+20180219.orig.tar.gz
 7f9fee61891dedc16f27b54b1e351db8a1b1daa5 4068 aufs_4.15+20180219-1.debian.tar.xz
 cd38d1244445156fd00d171220cdd75988912e4f 5941 aufs_4.15+20180219-1_amd64.buildinfo
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 4736380b506994c10e517f6abdf78689a6d8d7507d635c0893b6ca6ee865e647 2009 aufs_4.15+20180219-1.dsc
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Files:
 54490a50f447db1d7569c275d9eff597 2009 kernel optional aufs_4.15+20180219-1.dsc
 362eb7ff7b501f0ed82672c90b183129 239797 kernel optional aufs_4.15+20180219.orig.tar.gz
 5bae440eae173629bce66b6e35187ce6 4068 kernel optional aufs_4.15+20180219-1.debian.tar.xz
 965dd2684fa1156b1586d8073f4d02b4 5941 kernel optional aufs_4.15+20180219-1_amd64.buildinfo

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Message #121 received at 886329@bugs.debian.org (full text, mbox, reply):

From: intrigeri <intrigeri@debian.org>

To: sfjro@users.sourceforge.net

Cc: 886329@bugs.debian.org

Subject: Re: [Filesystems-devel] Bug#886329: Bug#886329: Bug#886329: aufs-dkms: Cannot use aufs union mount with Linux 4.14.7-1: kernel BUG at /var/lib/dkms/aufs/4.14+20171218/build/fs/aufs/finfo.c:113

Date: Sun, 25 Feb 2018 14:55:16 +0100

sfjro@users.sourceforge.net:
> sfjro@users.sourceforge.net:
>> Thanx for the interesting bug report.
>> Although I could not reproduce the bug, I'm afraid it is an aufs
>> problem. I will try more and investigate it, but it may take some time.

> On the report, I can see that you use aufs in qemu.
> Would you kindly tell me how you invoked it? I mean the exact command
> line.

Sure. Here's the command line libvirt generated:

  qemu-system-x86_64 -enable-kvm -name guest=sid-desktop,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-18-sid-desktop/master-key.aes -machine pc-i440fx-2.3,accel=kvm,usb=off,dump-guest-core=off -cpu Haswell-noTSX,vme=on,ss=on,vmx=on,f16c=on,rdrand=on,hypervisor=on,arat=on,tsc_adjust=on,xsaveopt=on,pdpe1gb=on,abm=on -m 2048 -realtime mlock=off -smp 4,sockets=4,cores=1,threads=1 -uuid 213ff882-ce4b-035d-e2b1-9059d66cd67d -no-user-config -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/domain-18-sid-desktop/monitor.sock,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot menu=off,strict=on -device piix3-usb-uhci,id=usb,bus=pci.0,addr=0x1.0x2 -device ahci,id=sata0,bus=pci.0,addr=0x5 -device virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x7 -device usb-hub,id=hub0,bus=usb.0,port=1 -drive if=none,id=drive-ide0-1-0,readonly=on -device ide-cd,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive file=/var/lib/libvirt/images/sid-desktop.img,format=qcow2,if=none,id=drive-virtio-disk0 -device virtio-blk-pci,scsi=off,bus=pci.0,addr=0x8,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 -netdev tap,fd=26,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=52:54:00:05:17:47,bus=pci.0,addr=0x3 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -device virtio-tablet-pci,id=input0,bus=pci.0,addr=0x9 -device virtio-keyboard-pci,id=input2,bus=pci.0,addr=0xa -spice port=5947,addr=127.0.0.1,disable-ticketing,seamless-migration=on -device virtio-vga,id=video0,max_outputs=1,bus=pci.0,addr=0x2 -device intel-hda,id=sound0,bus=pci.0,addr=0x4 -device hda-duplex,id=sound0-codec0,bus=sound0.0,cad=0 -chardev spicevmc,id=charredir0,name=usbredir -device usb-redir,chardev=charredir0,id=redir0,bus=usb.0,port=1.1 -chardev spicevmc,id=charredir1,name=usbredir -device usb-redir,chardev=charredir1,id=redir1,bus=usb.0,port=1.2 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x6 -msg timestamp=on

Note that this bug happens on bare metal too e.g. with
https://mirrors.wikimedia.org/tails/stable/tails-amd64-3.5/tails-amd64-3.5.iso

> Because I cannot reproduce the problem on my test machine, intel
> core2duo (I know this is old machine). Do you have more cpu cores? Do
> you think that more and more cores get more chances to reproduce?

I've just retried with different numbers of vCPUs allocated to the VM
and CONFIG_AUFS_DEBUG enabled. I could reproduce the bug with 1 vCPU,
2 vCPUs, and with my original settings (4 vCPUs).

Cheers,
-- 
intrigeri

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