[SOLVED] /dev/shm wrong permissions. How do I make fix permanent?

[TonyPH12345]

Hi, folks.

I recently compile Kernel 2.6.34 (to fix the AMD PowerNow issue with 1055T processor, and it worked!)

However, the device

/dev/shm

starts up at boot as Read-Only.

Google Chrome requires this device to be user-writable, or it won't start up. Presumably, the stock kernels (and all that are updated) have it set to User-Write. I have not noticed any other ill effects with the permission being read-only.

If I do:

sudo chmod a+w /dev/shm

Everything will work from there, but each time I reboot, I have to do that.

How do I make that permission-change permanent?

[parish]

Try this; it used to work for the sound devices so by extension I'm assuming it will work here as well...

Create a file: /etc/security/console.perms.d/99-shm.perms that contains:

# device classes -- these are shell-style globs
<shm>=/dev/shm /dev/shm/*

# permission definitions
<console>  0666 <shm>      0600 root

...then log out and back in. You should be good to go.


Edited to add that you may actually have to reboot in order for the console.perms.d to be re-sourced. There is probably a less drastic way to reinitialize them, but I don't know how myself...

[TonyPH12345]

Parish: No dice.

[bodhi.zazen]

I would add

chmod a+w /dev/shm

to /etc/rc.local

[TonyPH12345]

bodhi: I was looking for something MUCH more complicated! That, of course, worked like a charm. Thanks for that!

If anyone could tell me what I munged in the compile that started this, I'd be open to commentary!

[parish]

Originally Posted by TonyPH12345

Parish: No dice.

Apologies for the red herring!

I just confirmed that this no longer works for my sound devices either. Very puzzling as I've been doing this since the dawn of the fedora age and it is in fact the 'correct' way to set device permissions.

Now I'm curious as to what has changed to cause this. I'll post back when/if I figure it out...

[lwfitz]

Originally Posted by bodhi.zazen

I would add

chmod a+w /dev/shm

to /etc/rc.local

Worked perfect on Crunchbang 10.......... Ive been trying for the last 3 hours to figure this out! Thank you so much!

[hazyl]

I have been having problems with the permissions to the audio and video devices on my Fedora Core 6 (FC6) system. In this case, udev creates the devices at boot time and sets the permissions. However, these were set to "0600 root" and modifying the udev rules did not fix it..

The modifications suggested by parish for /etc/security/console.perms.d and applied to the audio and the video devices, but using "0600 root.users" permissions, and along with the right /etc/modprobe.conf fixed the problem once and for all.

Thanks for the suggestion.