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

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:

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: SXI ADMIN

The author is the creator of SXI LLC and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.