Re: [patch 8/8] x86/vdso: Implement __vdso_futex_robust_try_unlock()

From: Thomas Gleixner

Date: Thu Mar 19 2026 - 19:39:39 EST


On Thu, Mar 19 2026 at 10:08, Peter Zijlstra wrote:
> On Thu, Mar 19, 2026 at 09:53:53AM +0100, Florian Weimer wrote:
>> If the the /lib/modules/$(uname -r)/vdso/vdsoNN.so path is standard, we
>> can use it in the link map, at the expense of an additional system call
>> during process startup. It isn't just a performance cost. We've seen
>> seccomp filters that kill the process on uname calls.
>
> I've always though it would be a good idea to expose vdsoNN.so somewhere
> in our virtual filesystem, either /proc or /sys or whatever.

Yes, exposing this through a virtual fs would be really sensible. It's
not a lot of data.

VDSO debug info is ~40K extra per vdsoNN.so and vdsoNN.so.dbg compresses
to ~25k with zstd. Converting that whole thing to a binary blob and bake
it into the kernel is nor rocket science.

Thanks,

tglx