Description of problem: A normal user is able to create a file in /run/user/<user number> that completely consumes all of the space. Thus when system tasks need to allocate space in tmpfs, they cancel. Version-Release number of selected component (if applicable): Fedora 18 Alpha RC3 How reproducible: as a normal user: [Me@tower20 /]$ dd if=/dev/zero of=/run/user/1000/test bs=1024 count=50000000000 dd: writing '/run/user/1000/test': No space left on device 2007521+0 records in 2007520+0 records out 2055700480 bytes (2.1 GB) copied, 109.335 s, 18.8 MB/s Steps to Reproduce: 1. log into a terminal screen as a normal user 2. run the dd command 3. try mounting filesystem afterwards, it cancels with no room left on device. Actual results: All tmpfs space in /run is consumed Expected results: I really don't think a user without any privileges should be able to bring a system to it's knees with just one simple command. Additional info:
Well, that's a general problem that tmpfs knows no quota right now, and is not specific to /run, but is also intrinsic to /dev/shm an /tmp which are publicly writable tmpfs. We really need quota on tmpfs, and this has been requested before. Reassigning to kernel. There have been patches for this already: https://lwn.net/Articles/466376/ This patch introducing RLIMIT_TMPFSQUOTA makes a ton of sense to me, but I am fine with any other solution too.
*** This bug has been marked as a duplicate of bug 693253 ***