LEROY Christophe <christophe.le...@c-s.fr> writes: > Michael Ellerman <m...@ellerman.id.au> a écrit : > >> LEROY Christophe <christophe.le...@c-s.fr> writes: >> >>> Benjamin Herrenschmidt <b...@kernel.crashing.org> a écrit : >>> >>>> When hitting below a VM_GROWSDOWN vma (typically growing the stack), >>>> we check whether it's a valid stack-growing instruction and we >>>> check the distance to GPR1. This is largely open coded with lots >>>> of comments, so move it out to a helper. >>> >>> Did you have a look at the following patch ? It's been waiting for >>> application for some weeks now. >>> https://patchwork.ozlabs.org/patch/771869 >> >> I actually merged it last merge window, but found I had no good way to >> test it, so I took it out again until I can write a test case for it. >> >> The way I realised it wasn't being tested was by removing all the >> store_updates_sp logic entirely and having my system run happily for >> several days :} > > Which demonstrates how unlikely this is, hence doing that get_user() > at every fault is waste of time.
Yes I agree. > How do you plan to handle that in parralele to ben's serie ? Not sure :) > I'll be back from vacation next week and may help finding a way to > test that. (A test program using alloca() ?) I was thinking hand-crafted asm, but that might be a pain to get working for 32 & 64-bit, in which case alloca() might work. cheers