Re: [PATCH 09/16] sparc64: use the generic get_user_pages_fast code

[David Miller]

From: "Dmitry V. Levin" <ldv@xxxxxxxxxxxx>
Date: Thu, 18 Jul 2019 00:59:56 +0300

> So this ended up as commit 7b9afb86b6328f10dc2cad9223d7def12d60e505
> (thanks to Anatoly for bisecting) and introduced a regression: 
> futex.test from the strace test suite now causes an Oops on sparc64
> in futex syscall.
> 
> Here is a heavily stripped down reproducer:

Does not reproduce for me on a T4-2 machine.

So this problem might depend on the type of system you are on,
I suspect it's one of those "pre-Niagara vs. Niagara and later"
situations because that's the dividing line between two set of
wildly different TLB and cache management methods.

What kind of machine are you on?