POSIX shared memory and dying jails
- Reply: James Gritton : "Re: POSIX shared memory and dying jails"
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Date: Fri, 25 Jun 2021 14:41:00 UTC
Hi, It seems like non-anonymous POSIX shared memory is not freed automatically when a jail is removed and keeps it in a dying state, until the shared memory segment is deleted manually. See below for the most basic example: [root@jailhost ~]# jail -c path=/ command=/bin/sh # posixshmcontrol create /removeme # exit [root@jailhost ~]# jls -dv -j shmtest dying true So at this point, the jail is stuck in a dying state. Checking POSIX shared memory segments shows the shared memory segment which is stopping the jail from crossing the Styx: [root@jailhost ~]# posixshmcontrol list MODE OWNER GROUP SIZE PATH rw------- root wheel 0 /removeme After removing the shared memory segment manually... [root@jailhost ~]# posixshmcontrol rm /removeme the jail passes away peacefully: [root@jailhost ~]# jls -dv -j shmtest dying jls: jail "shmtest" not found I wonder if it wouldn't make sense to always remove POSIX shared memory created by a jail automatically when it's removed. Best, Michael -- Michael Gmelin