Messages in this thread | | | Subject | Re: Linux 2.2.0pre2 | From | Andi Kleen <> | Date | 31 Dec 1998 18:20:09 +0100 |
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In article <Pine.LNX.3.95.981230231437.442A-100000@penguin.transmeta.com>, torvalds@transmeta.com (Linus Torvalds) writes: > - fix for an attack where you could cause a complete and utter lockup of > the kernel as a normal user. Thanks to Michael Chastain for keeping the > faith on this one and reminding me to fix it.
This is harmless compared to the attacks possible with /proc/<pid>/mem @) All functions in fs/proc/mem.c are super-racy (the process/mm structure may go away while it sleeps) and have other problems. Also they are completely unreliable to use because they don't fault in pages. Alan's acX patches have a patch that fix most races, except a few problems in the mem_mmap() range checking. Fixing mmap completely is hard because doing it full may lead to shared anonymous mappings.
These problems are in 2.0 too.
> If you haven't had problems with pre1, there should be no major cause to > look at pre2. But if you haven't even looked at pre1 yet, please consider > looking at the pre-2.2.0 kernels before it's too late. I'm going to be > extremely rude to people who knew better but didn't test out the pre- > kernels and then send me bug-reports on the released 2.2.0.
Out of memory handling seems to be poor in 2.2.0pre1. It gets into a strange swap storm that does not do full HD bandwidth swapping, but small bursts of IO with pauses.
-Andi
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