[PATCH] ARM: hw_breakpoint: Handle inexact watchpoint addresses

[Doug Anderson]

Hi,

On Thu, Aug 6, 2020 at 8:41 AM Russell King - ARM Linux admin
<linux at armlinux.org.uk> wrote:
>
> On Thu, Aug 06, 2020 at 08:05:10AM -0700, Doug Anderson wrote:
> > Hi,
> >
> > On Mon, Dec 2, 2019 at 8:36 AM Doug Anderson <dianders at chromium.org> wrote:
> > >
> > > Hi,
> > >
> > > On Wed, Nov 20, 2019 at 11:18 AM Will Deacon <will at 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 at 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 at 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?
>
> Yes.  Stephen Rothwell raised a complaint against it, which you were
> copied with:

Was a mailing list copied?  If so, do you have a lore.kernel.org link?
 I certainly don't see the email so I can only assume it made it to
spam.  That's unfortunate.


> > Hi all,
> >
> > Commit
> >
> >   116375be0461 ("ARM: 8944/1: hw_breakpoint: Handle inexact watchpoint addresses")
> >
> > is missing a Signed-off-by from its author.
>
> My reply to Stephen's email was:
>
> > Thanks Stephen, patch dropped.
> >
> > It looks like Doug used his "m.disordat.com" address to submit the
> > patch through the web interface, and there was no From: in the patch
> > itself, so that was used as the patch author.  However, as you spotted,
> > it was signed off using Doug's "chromium.org" address.
> >
> > I think it's time to make the patch system a bit more strict, checking
> > that the submission address is mentioned in a signed-off-by tag
> > somewhere in the commit message.
> >
> > Doug, the patch system does have your "chromium.org" address, if that's
> > the one you want to use as the author, please submit using that instead.
> > Thanks.
> >
> > Russell.
>
> Neither email got a response from you, so the patch was dropped and
> nothing further happened.

OK, I guess I'll have to rebase and resend.

-Doug