[PATCH v3 04/11] um: Don't use vfprintf() for os_info()

[Johannes Berg]

On Fri, 2024-01-05 at 09:12 +0100, Benjamin Berg wrote:
> > Another option is giving the helper threads more memory, we don't have
> > that many.
> > Did you explore this option already?
> 
> I had not really considered that.
> 
> One thing though is that userspace_tramp calls os_info while working
> with the stub stack. So that also means setting STUB_DATA_PAGES to 2.
> But, I suspect we may want to do that anyway eventually to fit the ever
> increasing mcontext size for all the AVX512 registers and such.

That'll probably happen eventually regardless ...

> As I said, I think that is fine to do.

But I'm not sure it's a good solution to give more stack space to the
threads and think/hope that glibc won't make more assumptions about the
amount of space it can use ... who knows if it uses alloca() inside
somewhere, for example? After all, userspace stacks are multiple
megabytes by default?

johannes