I'm posting again. This bug still exists. Easily reproducible. Here's how. (You NEED to be able to essentially use up RAM to see this bug in action)
Tested on a 3GB desktop (Core 2 Quad), running Live Ubuntu 18.10 LTS off of a flash drive (pendrivelinux.com). Kernel 4.18.0-10. FF 63.0. I set the download folder to a dir on the hard drive so as not to deliberately stress free RAM. With the system showing about 1.5GB free (System Monitor/Resources tab), trying to d/l this 1.25GB ROM image from Mega ( https://mega.nz/#!KUAyRKjJ!3hALO7dkuyFdE41BTWf1OfHaZmdTA-Kzd8q0HYiMbYs ), the d/l gets to 100% but system monitor shows RAM at 97% or 98%, the flash drive lights up and stays lit. System frozen, as I've reported previously with my other laptops. I've mitigated this on the laptops because they now have 8GB of RAM. BUT-- even then, I can STILL crash those systems using Live Debian (or whatever flavor). It just takes more stressing (more open tabs, bigger d/l's, whatever) to get there, but it does. Quite the blackpill that Linux memory management has the serious flaw un-addressed for 13 years now. It's very easy to reproduce on *any* 64-bit system following the guidelines above. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/159356 Title: When DMA is disabled system freeze on high memory usage Status in linux package in Ubuntu: Incomplete Status in linux package in Arch Linux: New Bug description: I run a batch matlab job server here at my lab, running Dapper 6.06 (for the LTS). One of the users has submitted a very memory-consuming job, which successfully crashes the server. Upon closer inspection, the crash happens like this: 1. I run matlab with the given file (as an ordinary, unpriveleged user) 2. RAM usage quickly fills up 3. Once the RAM meter hits 100%, the system freezes: All SSH connections freeze up, and while switching VTs directly on the machine works, no new processes run - so one can't log in, or do anything if he is logged in. (Sometimes typing doesn't work at all) Note that the swap - while 7 gigs of it are available - is never used. (The machine has 7 gigs of RAM as well) I've tried the same on my Gutsy 32-bit box, and there was no system freezeup - matlab simply notified that the system was out of memory. However, it did this once memory was 100% in use - and still, swap didn't get used at all! (Though it is mounted correctly and shows up in "top" and "free"). So first thing's first - I'd like to eliminate the crash issue. I suppose I could switch the server to 32-bit, but I think that would be a performance loss, considering that it does a lot of heavy computation. There is no reason, however, that this should happen on a 64-bit machine anyway. Why does it? WORKAROUND: Enabling DMA in the BIOS To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/159356/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
