From: Chris Brandt <Chris.Brandt@renesas.com>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-embedded@vger.kernel.org" <linux-embedded@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v2 4/5] cramfs: add mmap support
Date: Tue, 29 Aug 2017 20:11:22 +0000 [thread overview]
Message-ID: <SG2PR06MB1165928D73A113D94DA864EF8A9F0@SG2PR06MB1165.apcprd06.prod.outlook.com> (raw)
In-Reply-To: <nycvar.YSQ.7.76.1708291552240.2606@knanqh.ubzr>
On Tuesday, August 29, 2017, Nicolas Pitre wrote:
> On Tue, 29 Aug 2017, Chris Brandt wrote:
>
> > On Monday, August 28, 2017, Nicolas Pitre wrote:
> > > OK I moved the lock promotion right at the beginning _before_
> validating
> > > the split point. Also got a reference on the file to make sure that
> > > hasn't changed too.
> > >
> > > > While we are at it, what happens if you mmap 120Kb, then munmap()
> the
> > > middle
> > > > 40Kb. Leaving two 40Kb VMAs with 40Kb gap between them, that is.
> Will
> > > your
> > > > ->vm_private_data be correct for both?
> > >
> > > It wouldn't, but I now changed it to contain absolute values so now it
> > > will. And if the split point lands in the hole then the code just
> > > readjusts the pgoff at the beginning of the remaining part.
> > >
> > > Here's the revised patch:
> >
> >
> > For whatever it's worth, as soon as I moved to 4.13-rc7,
> > CONFIG_CRAMFS_PHYSMEM=y crashes my XIP_KERNEL system before it can even
> > get to any console output.
> >
> > (both the old patch and the new patch)
> >
> > If CONFIG_CRAMFS_PHYSMEM is not set, my XIP system boots fine.
> >
> > However, if I boot -rc7 as a uImage, the new patch works just as good as
> > the old patch.
>
> When not a uImage, do you mean by that a XIP kernel?
Yes, CONFIG_XIP_KERNEL.
> If so you should
> know by now from that other thread on LAK that the XIP linker script is
> broken and probably just worked by luck till now. Still, if you could
> bisect between -rc4 and -rc7 and pinpoint the change that makes it not
> work that would be better than speculations.
Note that everything else seem OK when CONFIG_XIP_KERNEL=y. It's just
when CONFIG_XIP_KERNEL=y CONFIG_CRAMFS_PHYSMEM=y which is odd. So hopefully
that means it will be easy to track down.
Chris
next prev parent reply other threads:[~2017-08-29 20:11 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-16 17:35 [PATCH v2 0/5] cramfs refresh for embedded usage Nicolas Pitre
2017-08-16 17:35 ` [PATCH v2 1/5] cramfs: direct memory access support Nicolas Pitre
2017-08-16 18:28 ` Chris Brandt
2017-08-16 19:44 ` Nicolas Pitre
2017-08-16 17:35 ` [PATCH v2 2/5] cramfs: make cramfs_physmem usable as root fs Nicolas Pitre
2017-08-16 17:35 ` [PATCH v2 3/5] cramfs: implement uncompressed and arbitrary data block positioning Nicolas Pitre
2017-08-16 18:28 ` Chris Brandt
2017-08-16 17:35 ` [PATCH v2 4/5] cramfs: add mmap support Nicolas Pitre
2017-08-16 18:28 ` Chris Brandt
2017-08-28 6:46 ` Al Viro
2017-08-28 13:29 ` Nicolas Pitre
2017-08-28 14:23 ` Al Viro
2017-08-28 19:17 ` Nicolas Pitre
2017-08-29 19:38 ` Chris Brandt
2017-08-29 20:00 ` Nicolas Pitre
2017-08-29 20:11 ` Chris Brandt [this message]
2017-08-31 2:29 ` Chris Brandt
2017-08-16 17:35 ` [PATCH v2 5/5] cramfs: rehabilitate it Nicolas Pitre
2017-08-31 2:30 ` [PATCH v2 0/5] cramfs refresh for embedded usage Chris Brandt
2017-08-31 3:03 ` Nicolas Pitre
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