Re: [PATCH AUTOSEL 4.14 05/14] binder: take read mode of mmap_sem in binder_alloc_free_page()

[Sasha Levin]

On Thu, Aug 29, 2019 at 10:10:52AM -0500, Tyler Hicks wrote:
> Hello, Sasha!
>
> On 2019-08-29 06:50:34, Sasha Levin wrote:
> > From: Tyler Hicks <tyhicks@xxxxxxxxxxxxx>
> >
> > [ Upstream commit 60d4885710836595192c42d3e04b27551d30ec91 ]
> >
> > Restore the behavior of locking mmap_sem for reading in
> > binder_alloc_free_page(), as was first done in commit 3013bf62b67a
> > ("binder: reduce mmap_sem write-side lock"). That change was
> > inadvertently reverted by commit 5cec2d2e5839 ("binder: fix race between
> > munmap() and direct reclaim").
> >
> > In addition, change the name of the label for the error path to
> > accurately reflect that we're taking the lock for reading.
> >
> > Backporting note: This fix is only needed when *both* of the commits
> > mentioned above are applied. That's an unlikely situation since they
> > both landed during the development of v5.1 but only one of them is
> > targeted for stable.
>
> This patch isn't meant to be applied to 4.14 since commit 3013bf62b67a
> ("binder: reduce mmap_sem write-side lock") was never brought back to
> 4.14.
>
> My backporting note above isn't helpful for AUTOSEL purposes. Do you
> have a suggestion for what I could have done in the patch tags to convey
> that guidance to AUTOSEL?

Hey Tyler,

No, this is just me messing up. AUTOSEL actually handled this well.

What happened here you ask? This series is basically a set of patches
that fix a different fix that went into stable. It didn't go through the
regular AUTOSEL flow and I goofed up manually. Sorry for the noise, I've
dropped the patch.

--
Thanks,
Sasha