[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

intrigeri at debian.org intrigeri at debian.org
Thu Jan 4 14:13:03 UTC 2018 

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

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