Cinelerra: MWindow::init_shm: /proc/sys/kernel/shmmax is 0x1000000 It should be at least 0x7ffffff

Posted on in Categories , last updated July 10, 2012

I‘m trying to use Cinelerra video editing and compositing software under Linux operating systems. However, I’m getting the following error:

MWindow::init_shm: /proc/sys/kernel/shmmax is 0x1000000.
It should be at least 0x7ffffff for cinelerra.

How do I fix this problem?

Before running Cinelerra you need to increase the value of shmmax. This value can be used to query and set the run time limit on the maximum shared memory segment size that can be created. Shared memory segments up to 1Gb are now supported in the kernel. This value defaults to SHMMAX. If this value is smaller you will see the error as follows on screen:

Cinelerra Error

To fix this problem edit /etc/sysctl.conf file, enter: the following line (must be run as the root):
# vi /etc/sysctl.conf
Append the following line


Save and close the file. Type the following command to activate the settings:
# sysctl -p

Posted by: Vivek Gite

The author is the creator of nixCraft and a seasoned sysadmin and a trainer for the Linux operating system/Unix shell scripting. He has worked with global clients and in various industries, including IT, education, defense and space research, and the nonprofit sector. Follow him on Twitter, Facebook, Google+.

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