[stable] binder: fix race between munmap() and direct reclaim

[stable] binder: fix race between munmap() and direct reclaim

[Ben Hutchings]

There are commits in the 4.14, 4.19 and 5.0 stable branches that claim
to be backports of:

commit 26528be6720bb40bc8844e97ee73a37e530e9c5e
Author: Todd Kjos <tkjos@android.com>
Date:   Thu Feb 14 15:22:57 2019 -0800

    binder: fix handling of misaligned binder object

However the source changes actually match:

commit 5cec2d2e5839f9c0fec319c523a911e0a7fd299f
Author: Todd Kjos <tkjos@android.com>
Date:   Fri Mar 1 15:06:06 2019 -0800

    binder: fix race between munmap() and direct reclaim

So far as I can see, the former fixes a bug only introduced in 5.1 and
the latter fixes an older bug, so the changes are correct and only the
metadata is not.

Similar mix-ups have happened before and I'm a little disturbed that
this keeps happening.  In any case, you may want to revert and re-apply 
with correct metadata.

Ben.

-- 
Ben Hutchings, Software Developer                         Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom

Re: [stable] binder: fix race between munmap() and direct reclaim

[Greg Kroah-Hartman]

On Mon, May 27, 2019 at 10:09:32PM +0100, Ben Hutchings wrote:
> There are commits in the 4.14, 4.19 and 5.0 stable branches that claim
> to be backports of:
> 
> commit 26528be6720bb40bc8844e97ee73a37e530e9c5e
> Author: Todd Kjos <tkjos@android.com>
> Date:   Thu Feb 14 15:22:57 2019 -0800
> 
>     binder: fix handling of misaligned binder object
> 
> However the source changes actually match:
> 
> commit 5cec2d2e5839f9c0fec319c523a911e0a7fd299f
> Author: Todd Kjos <tkjos@android.com>
> Date:   Fri Mar 1 15:06:06 2019 -0800
> 
>     binder: fix race between munmap() and direct reclaim
> 
> So far as I can see, the former fixes a bug only introduced in 5.1 and
> the latter fixes an older bug, so the changes are correct and only the
> metadata is not.
> 
> Similar mix-ups have happened before and I'm a little disturbed that
> this keeps happening.  In any case, you may want to revert and re-apply 
> with correct metadata.

Note, these backports came directly from Todd, so he can provide more
information about them.  Todd, did something get messed up on your end
and do we need to include another patch to fix this up?

thanks,

greg k-h

Re: [stable] binder: fix race between munmap() and direct reclaim

[Todd Kjos]

Greg,

I'm really confused. [1] was my submittal to stable for "binder: fix
race between munmap() and direct reclaim" which I think looks correct.

For "binder: fix handling of misaligned binder object", I only
submitted to LKML [2]. But then I see [3] for 4.14 (that looks
incorrect as Ben pointed out).

So the result is that fix is present in the LTS trees where it is
needed, but it has the wrong commit message and headline.

I agree with Ben that the cleanest approach is to revert and apply the
correct version (to 4.14, 4.19, 5.0). I think the correct version is
the one I sent [1], but please let me know if you see something I
screwed up or if you need me to do something.

[1] https://www.spinics.net/lists/stable/msg299033.html
[2] https://lkml.org/lkml/2019/2/14/1235
[3] https://lkml.org/lkml/2019/4/30/650

-Todd


On Tue, May 28, 2019 at 9:34 AM Todd Kjos <tkjos@google.com> wrote:
>
> Probably my screw-up. I was working on both of those bug fixes at about the same time. I'll investigate what happened.
>
> On Mon, May 27, 2019 at 11:51 PM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote:
>>
>> On Mon, May 27, 2019 at 10:09:32PM +0100, Ben Hutchings wrote:
>> > There are commits in the 4.14, 4.19 and 5.0 stable branches that claim
>> > to be backports of:
>> >
>> > commit 26528be6720bb40bc8844e97ee73a37e530e9c5e
>> > Author: Todd Kjos <tkjos@android.com>
>> > Date:   Thu Feb 14 15:22:57 2019 -0800
>> >
>> >     binder: fix handling of misaligned binder object
>> >
>> > However the source changes actually match:
>> >
>> > commit 5cec2d2e5839f9c0fec319c523a911e0a7fd299f
>> > Author: Todd Kjos <tkjos@android.com>
>> > Date:   Fri Mar 1 15:06:06 2019 -0800
>> >
>> >     binder: fix race between munmap() and direct reclaim
>> >
>> > So far as I can see, the former fixes a bug only introduced in 5.1 and
>> > the latter fixes an older bug, so the changes are correct and only the
>> > metadata is not.
>> >
>> > Similar mix-ups have happened before and I'm a little disturbed that
>> > this keeps happening.  In any case, you may want to revert and re-apply
>> > with correct metadata.
>>
>> Note, these backports came directly from Todd, so he can provide more
>> information about them.  Todd, did something get messed up on your end
>> and do we need to include another patch to fix this up?
>>
>> thanks,
>>
>> greg k-h

Re: [stable] binder: fix race between munmap() and direct reclaim

[Greg Kroah-Hartman]

On Fri, May 31, 2019 at 01:09:53PM -0700, Todd Kjos wrote:
> Greg,
> 
> I'm really confused. [1] was my submittal to stable for "binder: fix
> race between munmap() and direct reclaim" which I think looks correct.
> 
> For "binder: fix handling of misaligned binder object", I only
> submitted to LKML [2]. But then I see [3] for 4.14 (that looks
> incorrect as Ben pointed out).
> 
> So the result is that fix is present in the LTS trees where it is
> needed, but it has the wrong commit message and headline.
> 
> I agree with Ben that the cleanest approach is to revert and apply the
> correct version (to 4.14, 4.19, 5.0). I think the correct version is
> the one I sent [1], but please let me know if you see something I
> screwed up or if you need me to do something.
> 
> [1] https://www.spinics.net/lists/stable/msg299033.html
> [2] https://lkml.org/lkml/2019/2/14/1235
> [3] https://lkml.org/lkml/2019/4/30/650

Can you send me a patch series that fixes things up properly?  I really
don't know exactly what to do here, sorry.

thanks,

greg k-h

Re: [stable] binder: fix race between munmap() and direct reclaim

[Todd Kjos]

On Tue, Jun 4, 2019 at 7:50 AM Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> On Fri, May 31, 2019 at 01:09:53PM -0700, Todd Kjos wrote:
> > Greg,
> >
> > I'm really confused. [1] was my submittal to stable for "binder: fix
> > race between munmap() and direct reclaim" which I think looks correct.
> >
> > For "binder: fix handling of misaligned binder object", I only
> > submitted to LKML [2]. But then I see [3] for 4.14 (that looks
> > incorrect as Ben pointed out).
> >
> > So the result is that fix is present in the LTS trees where it is
> > needed, but it has the wrong commit message and headline.
> >
> > I agree with Ben that the cleanest approach is to revert and apply the
> > correct version (to 4.14, 4.19, 5.0). I think the correct version is
> > the one I sent [1], but please let me know if you see something I
> > screwed up or if you need me to do something.
> >
> > [1] https://www.spinics.net/lists/stable/msg299033.html
> > [2] https://lkml.org/lkml/2019/2/14/1235
> > [3] https://lkml.org/lkml/2019/4/30/650
>
> Can you send me a patch series that fixes things up properly?  I really
> don't know exactly what to do here, sorry.

Sent. 2 patches for each of 4.14, 4.19, 5.0 (1/2=revert of bad patch,
2/2 apply good patch). Code ends up the same.

-Todd

Re: [stable] binder: fix race between munmap() and direct reclaim

[Greg Kroah-Hartman]

On Wed, Jun 05, 2019 at 09:43:53AM -0700, Todd Kjos wrote:
> On Tue, Jun 4, 2019 at 7:50 AM Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Fri, May 31, 2019 at 01:09:53PM -0700, Todd Kjos wrote:
> > > Greg,
> > >
> > > I'm really confused. [1] was my submittal to stable for "binder: fix
> > > race between munmap() and direct reclaim" which I think looks correct.
> > >
> > > For "binder: fix handling of misaligned binder object", I only
> > > submitted to LKML [2]. But then I see [3] for 4.14 (that looks
> > > incorrect as Ben pointed out).
> > >
> > > So the result is that fix is present in the LTS trees where it is
> > > needed, but it has the wrong commit message and headline.
> > >
> > > I agree with Ben that the cleanest approach is to revert and apply the
> > > correct version (to 4.14, 4.19, 5.0). I think the correct version is
> > > the one I sent [1], but please let me know if you see something I
> > > screwed up or if you need me to do something.
> > >
> > > [1] https://www.spinics.net/lists/stable/msg299033.html
> > > [2] https://lkml.org/lkml/2019/2/14/1235
> > > [3] https://lkml.org/lkml/2019/4/30/650
> >
> > Can you send me a patch series that fixes things up properly?  I really
> > don't know exactly what to do here, sorry.
> 
> Sent. 2 patches for each of 4.14, 4.19, 5.0 (1/2=revert of bad patch,
> 2/2 apply good patch). Code ends up the same.

Thanks for that, I'll queue them up soon.

greg k-h