Arch Linux

RLloque

Member

Registered: 2017-02-03

Posts: 40

Corrupt /dev/null (solved)

Hi everybody,

I just rebooted my system and now I have a problem with my /dev/null.
I (constantly) get the following error:

failed to open up /dev/null: permission denied

I recreated it by running

rm /dev/null
mknod /dev/null c 1 3
chmod 666 /dev/null

But every time I reboot the /dev/null is corrupted again.
How do I fix this?

Thank you

Last edited by RLloque (2020-08-25 16:41:28)

GaKu999

Member

From: US/Eastern

Registered: 2020-06-21

Posts: 696

Re: Corrupt /dev/null (solved)

Weird...
Post the outputs of the following after a clean boot, each command at a time:

stat /dev/null
ls /etc/tmpfiles.d
ls /usr/lib/tmpfiles.d
uname -a
pacman -Qkk filesystem

That should be enough to start looking for the cause, maybe...
Since the outputs will be small, just use code tags.

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RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

Thanks a lot!

stat /dev/null:

  File: /dev/null
  Size: 0         	Blocks: 0          IO Block: 4096   character special file
Device: 5h/5d	Inode: 1034        Links: 1     Device type: 1,3
Access: (0664/crw-rw-r--)  Uid: (    0/    root)   Gid: ( 1001/ dialout)
Access: 2020-08-25 16:46:05.946666834 +0200
Modify: 2020-08-25 16:46:05.946666834 +0200
Change: 2020-08-25 16:46:05.946666834 +0200
 Birth: -

ls /etc/tmpfiles.d (is empty)

ls /usr/lib/tmpfiles.d

arch.conf
bind.conf
colord.conf
dbus.conf
dhcpcd.conf
dmraid.conf
etc.conf
gvfsd-fuse-tmpfiles.conf
home.conf
journal-nocow.conf
legacy.conf
lightdm.conf
linux-firmware.conf
mkinitcpio.conf
nscd.conf
openvpn.conf
portables.conf
sshd.conf
static-nodes-permissions.conf
sudo.conf
systemd-nologin.conf
systemd-nspawn.conf
systemd-pstore.conf
systemd-tmp.conf
systemd.conf
tmp.conf
udisks2.conf
var.conf
x11.conf

uname -a

Linux temi 5.7.12-arch1-1 #1 SMP PREEMPT Fri, 31 Jul 2020 17:38:22 +0000 x86_64 GNU/Linux

pacman -Qkk filesystem

backup file: filesystem: /etc/fstab (Modification time mismatch)
backup file: filesystem: /etc/fstab (Size mismatch)
backup file: filesystem: /etc/group (Modification time mismatch)
backup file: filesystem: /etc/group (Size mismatch)
backup file: filesystem: /etc/gshadow (Modification time mismatch)
backup file: filesystem: /etc/gshadow (Size mismatch)
backup file: filesystem: /etc/hosts (Modification time mismatch)
backup file: filesystem: /etc/hosts (Size mismatch)
backup file: filesystem: /etc/passwd (Modification time mismatch)
backup file: filesystem: /etc/passwd (Size mismatch)
backup file: filesystem: /etc/resolv.conf (Modification time mismatch)
backup file: filesystem: /etc/resolv.conf (Size mismatch)
backup file: filesystem: /etc/shadow (Modification time mismatch)
backup file: filesystem: /etc/shadow (Size mismatch)
backup file: filesystem: /etc/shells (Modification time mismatch)
backup file: filesystem: /etc/shells (Size mismatch)
filesystem: 116 total files, 0 altered files

if it helps I also can't create pty's.
I just tried to open an xterm and got the following error in .xsession-errors

xterm: Error 32, errno 13: Permission denied
Reason: get_pty: not enough ptys

ls /dev | grep pty*

ptmx
pts  

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,372

Re: Corrupt /dev/null (solved)

The last time we had weird issues with ptys was because multiple instances of dhcpcd were enabled blasting the same interface, is that the case? what's your output for

find /etc/systemd -type l -exec test -f {} \; -print | awk -F'/' '{ printf ("%-40s | %s\n", $(NF-0), $(NF-1)) }' | sort -f

RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

It is:

dbus-org.freedesktop.nm-dispatcher.service | system
dbus-org.freedesktop.thermald.service    | system
dirmngr.socket                           | sockets.target.wants
display-manager.service                  | system
getty@tty1.service                       | getty.target.wants
gpg-agent-browser.socket                 | sockets.target.wants
gpg-agent-extra.socket                   | sockets.target.wants
gpg-agent-ssh.socket                     | sockets.target.wants
gpg-agent.socket                         | sockets.target.wants
NetworkManager-wait-online.service       | network-online.target.wants
NetworkManager.service                   | multi-user.target.wants
org.cups.cupsd.path                      | multi-user.target.wants
org.cups.cupsd.service                   | printer.target.wants
org.cups.cupsd.socket                    | sockets.target.wants
p11-kit-server.socket                    | sockets.target.wants
powertop.service                         | multi-user.target.wants
pulseaudio.socket                        | sockets.target.wants
remote-fs.target                         | multi-user.target.wants
sshd.service                             | multi-user.target.wants
thermald.service                         | multi-user.target.wants
xdg-user-dirs-update.service             | default.target.wants

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,741

Re: Corrupt /dev/null (solved)

Some udev rule going wild?
https://bbs.archlinux.org/viewtopic.php?id=256278

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RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

I don't have any custom rules.

udevadm test $(udevadm info -q path /dev/null)

generates:

Load module index
Parsed configuration file /usr/lib/systemd/network/99-default.link
Created link configuration context.
Reading rules file: /usr/lib/udev/rules.d/01-md-raid-creating.rules
Reading rules file: /usr/lib/udev/rules.d/10-dm.rules
Reading rules file: /usr/lib/udev/rules.d/11-dm-lvm.rules
Reading rules file: /usr/lib/udev/rules.d/13-dm-disk.rules
Reading rules file: /usr/lib/udev/rules.d/39-usbmuxd.rules
Reading rules file: /usr/lib/udev/rules.d/40-gphoto.rules
Reading rules file: /usr/lib/udev/rules.d/40-usb-media-players.rules
Reading rules file: /usr/lib/udev/rules.d/49-sane.rules
Reading rules file: /usr/lib/udev/rules.d/50-udev-default.rules
Reading rules file: /usr/lib/udev/rules.d/56-hpmud.rules
Reading rules file: /usr/lib/udev/rules.d/60-autosuspend.rules
Reading rules file: /usr/lib/udev/rules.d/60-block.rules
Reading rules file: /usr/lib/udev/rules.d/60-cdrom_id.rules
Reading rules file: /usr/lib/udev/rules.d/60-drm.rules
Reading rules file: /usr/lib/udev/rules.d/60-evdev.rules
Reading rules file: /usr/lib/udev/rules.d/60-fido-id.rules
Reading rules file: /usr/lib/udev/rules.d/60-input-id.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-alsa.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-input.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage-tape.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-storage.rules
Reading rules file: /usr/lib/udev/rules.d/60-persistent-v4l.rules
Reading rules file: /usr/lib/udev/rules.d/60-rfkill.rules
Reading rules file: /usr/lib/udev/rules.d/60-sensor.rules
Reading rules file: /usr/lib/udev/rules.d/60-serial.rules
Reading rules file: /usr/lib/udev/rules.d/63-md-raid-arrays.rules
Reading rules file: /usr/lib/udev/rules.d/64-btrfs-dm.rules
Reading rules file: /usr/lib/udev/rules.d/64-btrfs.rules
Reading rules file: /usr/lib/udev/rules.d/64-md-raid-assembly.rules
Reading rules file: /usr/lib/udev/rules.d/65-libwacom.rules
Reading rules file: /usr/lib/udev/rules.d/69-cd-sensors.rules
Reading rules file: /usr/lib/udev/rules.d/69-dm-lvm-metad.rules
Reading rules file: /usr/lib/udev/rules.d/69-libmtp.rules
Reading rules file: /usr/lib/udev/rules.d/69-md-clustered-confirm-device.rules
Reading rules file: /usr/lib/udev/rules.d/70-infrared.rules
Reading rules file: /usr/lib/udev/rules.d/70-joystick.rules
Reading rules file: /usr/lib/udev/rules.d/70-mouse.rules
Reading rules file: /usr/lib/udev/rules.d/70-power-switch.rules
Reading rules file: /usr/lib/udev/rules.d/70-touchpad.rules
Reading rules file: /usr/lib/udev/rules.d/70-uaccess.rules
Reading rules file: /usr/lib/udev/rules.d/71-seat.rules
Reading rules file: /usr/lib/udev/rules.d/73-seat-late.rules
Reading rules file: /usr/lib/udev/rules.d/75-net-description.rules
Reading rules file: /usr/lib/udev/rules.d/75-probe_mtd.rules
Reading rules file: /usr/lib/udev/rules.d/78-sound-card.rules
Reading rules file: /usr/lib/udev/rules.d/80-drivers.rules
Reading rules file: /usr/lib/udev/rules.d/80-libinput-device-groups.rules
Reading rules file: /usr/lib/udev/rules.d/80-net-setup-link.rules
Reading rules file: /usr/lib/udev/rules.d/80-udisks2.rules
Reading rules file: /usr/lib/udev/rules.d/84-nm-drivers.rules
Reading rules file: /usr/lib/udev/rules.d/85-nm-unmanaged.rules
Reading rules file: /usr/lib/udev/rules.d/90-alsa-restore.rules
Reading rules file: /usr/lib/udev/rules.d/90-libinput-fuzz-override.rules
Reading rules file: /usr/lib/udev/rules.d/90-nm-thunderbolt.rules
Reading rules file: /usr/lib/udev/rules.d/90-pulseaudio.rules
Reading rules file: /usr/lib/udev/rules.d/90-vconsole.rules
Reading rules file: /usr/lib/udev/rules.d/95-cd-devices.rules
Reading rules file: /usr/lib/udev/rules.d/95-dm-notify.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-csr.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-hid.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-hidpp.rules
Reading rules file: /usr/lib/udev/rules.d/95-upower-wup.rules
Reading rules file: /usr/lib/udev/rules.d/96-e2scrub.rules
Reading rules file: /usr/lib/udev/rules.d/99-fuse.rules
Reading rules file: /usr/lib/udev/rules.d/99-fuse3.rules
Reading rules file: /usr/lib/udev/rules.d/99-systemd.rules
Reading rules file: /etc/udev/rules.d/hid.rules
/etc/udev/rules.d/hid.rules:1 The line takes no effect, ignoring.
/etc/udev/rules.d/hid.rules:2 The line takes no effect, ignoring.
null: Failed to set owner/mode of /dev/null to uid=0, gid=1001, mode=0664: Operation not permitted
Unload module index
Unloaded link configuration context.
This program is for debugging only, it does not run any program
specified by a RUN key. It may show incorrect results, because
some values may be different, or not available at a simulation run.

DEVPATH=/devices/virtual/mem/null
DEVNAME=/dev/null
DEVMODE=0666
MAJOR=1
MINOR=3
ACTION=add
SUBSYSTEM=mem

I assume that this causes the problem?

null: Failed to set owner/mode of /dev/null to uid=0, gid=1001, mode=0664: Operation not permitted

seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,741

Re: Corrupt /dev/null (solved)

I don't have any custom rules.

So what's this?

pacman -Qo /etc/udev/rules.d/hid.rules
cat /etc/udev/rules.d/hid.rules

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RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

pacman -Qo /etc/udev/rules.d/hid.rules:

error: No package owns /etc/udev//rules.d//hid.rules

cat /etc/udev/rules.d/hid.rules:

KERNEL=="hidraw*",
SUBSYSTEM=="hidraw",
MODE="0664",
GROUP="dialout"

schard

Forum Moderator

From: Hannover

Registered: 2016-05-06

Posts: 2,702

Website

Re: Corrupt /dev/null (solved)

And this seems to somehow affect /dev/null.
Look at the mode and group.

Last edited by schard (2020-08-25 16:16:47)

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RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

I did add the group dialout recently while trying to connect a smartwatch via USB.

schard

Forum Moderator

From: Hannover

Registered: 2016-05-06

Posts: 2,702

Website

Re: Corrupt /dev/null (solved)

Then also add the product attrs to match like here:
https://github.com/signal11/hidapi/blob … -hid.rules
Otherwise it will obviously affect other devices as well.

Last edited by schard (2020-08-25 16:18:56)

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seth

Member

From: Won't reply 2 private help req

Registered: 2012-09-03

Posts: 77,741

Re: Corrupt /dev/null (solved)

Esp. remove the newlines…

/etc/udev/rules.d/hid.rules:1 The line takes no effect, ignoring.
/etc/udev/rules.d/hid.rules:2 The line takes no effect, ignoring.

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RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

I don't need the group any more.
Can I just delete it and the hid.rules, or might that cause further problems?

GaKu999

Member

From: US/Eastern

Registered: 2020-06-21

Posts: 696

Re: Corrupt /dev/null (solved)

Yes you can delete it safely...anyways the default /dev/null allows read/write by anyone...

What was the purpose or you forgot?
You can keep the group if not sure, but that hid.rule looks like trouble...

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loqs

Member

Registered: 2014-03-06

Posts: 19,048

Re: Corrupt /dev/null (solved)

The dialout group is not created on Arch as it is not used on Arch.  It is mapped to the uucp group.

https://github.com/archlinux/svntogit-p … oups.patch

RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

The purpose was to allow wine access to my USB ports in order to configure a Fitness tracker.
I will delete hid.rules now!

RLloque

Member

Registered: 2017-02-03

Posts: 40

Re: Corrupt /dev/null (solved)

Thanks a lot everyone, the problem is solved!