On Fri, 07.06.13 14:39, Bill Nottingham (notting@xxxxxxxxxx) wrote: > Lennart Poettering (mzerqung@xxxxxxxxxxx) said: > > Yes, it is. > > > > POSIX shared memory doesn't define any useful scheme for automatic > > removing of shared memory segments from /dev/shm after use. Hence, in > > order to make sure that left-over segments don't fill up /dev/shm > > forever PA will try to GC dead segments from /dev/shm on each > > start-up. For that it iterates through /dev/shm/pulse-shm*, tries to > > read the PID that is stored in there. When the PID still exists it goes > > to the next file. If the PID doesn't exist it unlinks the file and then > > goes to the next one. It's a simple scheme that works around the > > limitations of POSIX shm. Of course /dev/shm is a single namespace for > > all users, hence not all files can be opened, and that's totally cool > > and expected, and they will be skipped. > > > > Shared memory on Linux is a mess. Not automatic clean up, no quota > > limits, it's a sad story. If you care about security and reliability, it > > would be great doing something about this, so that arbitrary users > > cannot DoS the system this easily anymore... > > Any reason we don't run with namespaced /dev/shm vis-a-vis private /tmp? We kinda have that in XDG_RUNTIME_DIR now. /dev/shm is supposed to be shared among users I guess. If you want a user-specific namespace use XDG_RUNTIME_DIR instead, you will get pretty much the same semantics except that shm_open() needs to be replaced by open(). Lennart -- Lennart Poettering - Red Hat, Inc. -- devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/devel
