Re: [PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses

From: Doug Anderson <dianders@chromium.org>
To: Will Deacon <will@kernel.org>, Russell King <linux@armlinux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Pavel Labath <labath@google.com>,
	Pratyush Anand <panand@redhat.com>,
	Matthias Kaehlcke <mka@chromium.org>,
	Kazuhiro Inaba <kinaba@google.com>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Guenter Roeck <groeck@chromium.org>
Subject: Re: [PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses
Date: Thu, 6 Aug 2020 08:05:10 -0700	[thread overview]
Message-ID: <CAD=FV=WgoVN-scgT41R=6Toif2Zrskb3rNzZn_xbP_-ByZC1MA@mail.gmail.com> (raw)
In-Reply-To: <CAD=FV=Wntf0TCwdtNNvPY-CXX1VL_SZK8Y8yw1r=UfeayHfwgw@mail.gmail.com>

Hi,

On Mon, Dec 2, 2019 at 8:36 AM Doug Anderson <dianders@chromium.org> wrote:
>
> Hi,
>
> On Wed, Nov 20, 2019 at 11:18 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Sat, Oct 19, 2019 at 11:12:26AM -0700, Douglas Anderson wrote:
> > > This is commit fdfeff0f9e3d ("arm64: hw_breakpoint: Handle inexact
> > > watchpoint addresses") but ported to arm32, which has the same
> > > problem.
> > >
> > > This problem was found by Android CTS tests, notably the
> > > "watchpoint_imprecise" test [1].  I tested locally against a copycat
> > > (simplified) version of the test though.
> > >
> > > [1] https://android.googlesource.com/platform/bionic/+/master/tests/sys_ptrace_test.cpp
> > >
> > > Signed-off-by: Douglas Anderson <dianders@chromium.org>
> > > ---
> > >
> > >  arch/arm/kernel/hw_breakpoint.c | 96 ++++++++++++++++++++++++---------
> > >  1 file changed, 70 insertions(+), 26 deletions(-)
> >
> > Sorry for taking so long to look at this. After wrapping my head around the
> > logic again
>
> Yeah.  It was a little weird and (unfortunately) arbitrarily different
> in some places compared to the arm64 code.
>
>
> > I think it looks fine, so please put it into the patch system
> > with my Ack:
> >
> > Acked-by: Will Deacon <will@kernel.org>
>
> Thanks!  Submitted as:
>
> https://www.arm.linux.org.uk/developer/patches/viewpatch.php?id=8944/1

Oddly, I found that if I go visit that page now I see:

> - - - Note 2 submitted by Russell King on 17 Jan 2020 11:16:34 (UTC) - - -
> Moved to applied
>
> Applied to git-curr (misc branch).

Yet if I go check mainline the patch is not there.  This came to my
attention since we had my patch picked to the Chrome OS 4.19 tree and
suddenly recently got a stable merge conflict with "ARM: 8986/1:
hw_breakpoint: Don't invoke overflow handler on uaccess watchpoints".

Anyone know what happened here?

-Doug