Re: [34-longterm 167/179] futex: Fix regression with read onlymappings

[Paul Gortmaker]

[Re: [34-longterm 167/179] futex: Fix regression with read only mappings] On 15/05/2012 (Tue 12:51) Peter Zijlstra wrote:

> On Mon, 2012-05-14 at 21:38 -0700, Hugh Dickins wrote:
> > I don't know: I'm not NAKking it, I'm just waving a reddish flag,
> > and hoping that Peter will remember more, and have something more
> > constructive to say, than I can think of at this moment. 
> 
> Ha! you're very optimistic :-)
> 
> going by git log kernel/futex.c on a recent kernel the proposed patch
> should indeed be followed by your patch, but I can't seem to find more
> relevant patches.

Thanks a lot guys.  That is a dependency I'd never have come up with.

Willy -- this is probably of interest to you as well.   Hugh says that
commit e6780f7243 ("futex: Fix uninterruptible loop due to gate_area")
should be used if 9ea71503a8 ("futex: Fix regression with read only
mappings") is used.  The v2.6.32.46 added 9ea71503a8 (as d64ec7bb),
but I don't see a cherry pick of e6780f7243 in any v2.6.32.x yet.

Greg already applied it to 3.0.16 and 3.1.8 and it appeared in v3.2
by default, so no other active stable releases need to worry.

I had to change page_mapping --> page, since the 2.6.34 baseline does
not have a5b338f2b0b1ff73 ("thp: update futex compound knowledge")
[added to v2.6.38] which introduces the shadow variable page_mapping.

Paul.
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