Messages in this thread | | | Date | Mon, 25 Jul 2011 23:53:28 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86, AMD: Correct F15h IC aliasing issue |
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On Mon, Jul 25, 2011 at 04:06:45PM -0400, Ingo Molnar wrote: > > * Borislav Petkov <bp@amd64.org> wrote: > > > So yeah, the simpler fix works for processes mapping libraries in > > the same order but not for processes mapping a subset of libraries > > in a different order. > > but what is the proportion of 'good' versus bad alignment of > libraries, could you collect some stats on a representative enough, > fully booted up Linux system? > > Are only 1% of mappings 'bad'? 5%? 10%? 50%? We have no idea and the > actual number matters a lot.
Actually, it's hard to say what is a 'good' and 'bad' allocation. If they don't alias, they're always good :).
Anyway, I did some beginners awk-ery on a gentoo system with ca. 150 processes. Below is some data for the "r-xp" mappings.
ld-2.12.2.so, for example, is always loaded at an address with [14:12] = 000b while libc's addresses differ in those bits because a different number of allocations is being done between ld and libc, thus libc lands at different offsets.
I'll do a more comprehensive collection tomorrow and distribute the mappings by [14:12] value, that should give us a better idea.
/lib64/ld-2.12.2.so|r-xp|7f07f61d8000 1 /lib64/ld-2.12.2.so|r-xp|7f1d8be10000 1 /lib64/ld-2.12.2.so|r-xp|7f1ea7678000 1 /lib64/ld-2.12.2.so|r-xp|7f272e248000 1 /lib64/ld-2.12.2.so|r-xp|7f37acf88000 1 /lib64/ld-2.12.2.so|r-xp|7f49853f0000 1 /lib64/ld-2.12.2.so|r-xp|7f50c1460000 1 /lib64/ld-2.12.2.so|r-xp|7f59f58e0000 1 /lib64/ld-2.12.2.so|r-xp|7f63dc818000 1 /lib64/ld-2.12.2.so|r-xp|7f7267d70000 1 /lib64/ld-2.12.2.so|r-xp|7fa026ba0000 2 /lib64/ld-2.12.2.so|r-xp|7fa24de88000 1 /lib64/ld-2.12.2.so|r-xp|7fa604cf8000 1 /lib64/ld-2.12.2.so|r-xp|7fb07d418000 1 /lib64/ld-2.12.2.so|r-xp|7fc33cb78000 1 /lib64/ld-2.12.2.so|r-xp|7fd0c2770000 1 /lib64/ld-2.12.2.so|r-xp|7fd1e2a08000 1 /lib64/ld-2.12.2.so|r-xp|7fd214b18000 1 /lib64/ld-2.12.2.so|r-xp|7fda88a58000 1 /lib64/ld-2.12.2.so|r-xp|7fdb87d98000 1 /lib64/ld-2.12.2.so|r-xp|7fe42a588000 1 /lib64/ld-2.12.2.so|r-xp|7ffd79c08000 1 /lib64/libc-2.12.2.so|r-xp|7f07f4e3e000 1 /lib64/libc-2.12.2.so|r-xp|7f1d8b66d000 1 /lib64/libc-2.12.2.so|r-xp|7f1ea7315000 1 /lib64/libc-2.12.2.so|r-xp|7f272ceae000 1 /lib64/libc-2.12.2.so|r-xp|7f37acc25000 1 /lib64/libc-2.12.2.so|r-xp|7f498508d000 1 /lib64/libc-2.12.2.so|r-xp|7f50c0ca9000 1 /lib64/libc-2.12.2.so|r-xp|7f59f557d000 1 /lib64/libc-2.12.2.so|r-xp|7f63dc061000 1 /lib64/libc-2.12.2.so|r-xp|7f7267a0d000 1 /lib64/libc-2.12.2.so|r-xp|7fa02591d000 2 /lib64/libc-2.12.2.so|r-xp|7fa24d8a5000 1 /lib64/libc-2.12.2.so|r-xp|7fa604995000 1 /lib64/libc-2.12.2.so|r-xp|7fb07cc31000 1 /lib64/libc-2.12.2.so|r-xp|7fc33b7de000 1 /lib64/libc-2.12.2.so|r-xp|7fd0c1f89000 1 /lib64/libc-2.12.2.so|r-xp|7fd1e26a5000 1 /lib64/libc-2.12.2.so|r-xp|7fd2147b5000 1 /lib64/libc-2.12.2.so|r-xp|7fda884e8000 1 /lib64/libc-2.12.2.so|r-xp|7fdb87a35000 1 /lib64/libc-2.12.2.so|r-xp|7fe42a01c000 1 /lib64/libc-2.12.2.so|r-xp|7ffd79451000 1
Thanks.
-- Regards/Gruss, Boris.
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