[RFC PATCH 0/3] Improved ALSR

[Florian Weimer]

* Topi Miettinen:

> FYI, the effect of full ASLR of mmap() by kernel also seems small:
>
> # echo 3 >/proc/sys/kernel/randomize_va_space
> # time ./malloc-vs-sbrk
>
> real    0m19.489s
> user    0m1.263s
> sys     0m18.211s
> # time ./malloc-vs-sbrk 1
>
> real    0m19.532s
> user    0m1.148s
> sys     0m18.366s

The value 3 doesn't do anything in a mainline kernel.

I think you will see rather catastrophic effects if you have a workload
that triggers TLB misses.  I expect that the cost of walking page tables
increases dramatically with full ASLR.

Thanks,
Florian
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