permissions problem on /dev/shm after udev upgrade[SOLVED]

jserink · Veteran Joined: 30 Jan 2004 Posts: 1008

Hi All:

After my udev-200 upgrade (which I had put off for 3 weeks) everything network wise is fine...
my eth0 is not enp0s25 and wlan0 is wlp3s0. That all works....but I get this message when trying to start chromium:
[4601:4623:0425/221717:FATAL:shared_memory_posix.cc(176)] This is frequently caused by incorrect permissions on /dev/shm. Try 'sudo chmod 1777 /dev/shm' to fix.

Similar error when I try and start my VM with:
qemu-kvm -boot c -hda /home/jserink/VMs/Win_7_Pro.img -cdrom /home/jserink/CDs/virtio-win-0.1-49.iso -m 6291 -smp 2 -usb -net nic,vlan=0,model=virtio,macaddr=52:54:00:00:EE:07 -net vde -rtc base=localtime -no-quit -vga qxl -global qxl.vram_size=128000 -name Win7 -monitor telnet:127.0.0.1:12997,server,nowait,ipv4 -spice port=15900,addr=127.0.0.1,disable-ticketing -device virtio-serial-pci -device virtserialport,chardev=spicechannel0,name=com.redhat.spice.0 -chardev spicevmc,id=spicechannel0,name=vdagent &

Simple enough fix, at a root prompt I just to this:
chmod 1777 /dev/shm

But I should not have to do this.
I tried adding a 'rw' to fstab but that did not fix it:
jserinki7 jserink # cat /etc/fstab
# /etc/fstab: static file system information.
#
# noatime turns off atimes for increased performance (atimes normally aren't
# needed); notail increases performance of ReiserFS (at the expense of storage
# efficiency). It's safe to drop the noatime options if you want and to
# switch between notail / tail freely.
#
# The root filesystem should have a pass number of either 0 or 1.
# All other filesystems should have a pass number of 0 or greater than 1.
#
# See the manpage fstab(5) for more information.
#

# <fs> <mountpoint> <type> <opts> <dump/pass>

# NOTE: If your BOOT partition is ReiserFS, add the notail option to opts.
#/dev/sda2 /boot ext2 noauto,noatime 1 2
/dev/sda10 / ext4 noatime 0 1
/dev/sda5 none swap sw 0 0
/dev/sda6 /var ext4 noatime 0 0
/dev/sda7 /usr ext4 noatime 0 0
/dev/sda8 /opt ext4 noatime 0 0
/dev/sda9 /tmp ext4 noatime 0 0
/dev/sda11 /mnt/shr ext3 noatime 0 0
/dev/sda3 /mnt/WindowsC ntfs-3g unamsk=000,users,noatime,uid=jserink,gid=users 0 0
/dev/sda12 /home ext4 noatime 0 0
#/dev/cdrom /mnt/cdrom auto noauto,user 0 0
#/dev/fd0 /mnt/floppy auto noauto 0 0
proc /proc proc defaults 0 0
shm /dev/shm devtmpfs nodev,nosuid,noexec,rw 0 0
tmpfs /var/firefoxcache devtmpfs size=100M,mode=0777 0 0
#tmpfs /var/chromiumcache tmpfs size=100M,mode=0777 0 0
cache-chromium /home/jserink/.cache/chromium devtmpfs defaults,noatime,mode=1777 0 0

Any gurus know how to fix this?
I want to avoid and ungly bootup hack in the local.d directory.

Cheers,
john

Hu · Moderator Joined: 06 Mar 2007 Posts: 21586

Why are you mounting devtmpfs at /dev/shm? You should never mount devtmpfs explicitly.

PaulBredbury · Watchman Joined: 14 Jul 2005 Posts: 7310

I use in /etc/fstab:

jserink · Veteran Joined: 30 Jan 2004 Posts: 1008

SamuliSuominen · Posted: Sat Apr 27, 2013 7:42 am Post subject:

PaulBredbury · Watchman Joined: 14 Jul 2005 Posts: 7310

SamuliSuominen · Posted: Sat Apr 27, 2013 11:15 am Post subject:

jserink · Veteran Joined: 30 Jan 2004 Posts: 1008

I've removed the shm entry from my fstab and everything still works so it appears it does not need to be there.

Good tip.
jserink@jserinki7 ~ $ cat /etc/fstab
# /etc/fstab: static file system information.
#
# noatime turns off atimes for increased performance (atimes normally aren't
# needed); notail increases performance of ReiserFS (at the expense of storage
# efficiency). It's safe to drop the noatime options if you want and to
# switch between notail / tail freely.
#
# The root filesystem should have a pass number of either 0 or 1.
# All other filesystems should have a pass number of 0 or greater than 1.
#
# See the manpage fstab(5) for more information.
#

# <fs> <mountpoint> <type> <opts> <dump/pass>

# NOTE: If your BOOT partition is ReiserFS, add the notail option to opts.
#/dev/sda2 /boot ext2 noauto,noatime 1 2
/dev/sda10 / ext4 noatime 0 1
/dev/sda5 none swap sw 0 0
/dev/sda6 /var ext4 noatime 0 0
/dev/sda7 /usr ext4 noatime 0 0
/dev/sda8 /opt ext4 noatime 0 0
/dev/sda9 /tmp ext4 noatime 0 0
/dev/sda11 /mnt/shr ext3 noatime 0 0
/dev/sda3 /mnt/WindowsC ntfs-3g unamsk=000,users,noatime,uid=jserink,gid=users 0 0
/dev/sda12 /home ext4 noatime 0 0
#/dev/cdrom /mnt/cdrom auto noauto,user 0 0
#/dev/fd0 /mnt/floppy auto noauto 0 0
proc /proc proc defaults 0 0
#shm /dev/shm tmpfs nodev,nosuid,noexec,rw 0 0
tmpfs /var/firefoxcache devtmpfs size=100M,mode=0777 0 0
#tmpfs /var/chromiumcache tmpfs size=100M,mode=0777 0 0
cache-chromium /home/jserink/.cache/chromium devtmpfs defaults,noatime,mode=1777 0 0

Cheers,
john

boospy · Guru Joined: 07 Feb 2010 Posts: 308 Location: Austria

Ok, what is right here? I haven't an entry in the fstab, because i read that is deprecated for shm. But when i boot the system i see always a error message that shm is not mounted and should be, it is a Errormessage when the kernel starts. For example, here is needet: http://wiki.gentoo.org/wiki/Steam#Kernel
I have steam, but never mounted shm...
But when i do an