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From: John Stultz <john.stultz@linaro.org>
Date: Tue, 8 Aug 2017 10:34:47 -0700
Message-ID: <CALAqxLXaigM2YyoHXYakJOtyq=nvUbRGeN6skV6y2-D6idKz7w@mail.gmail.com>
Subject: Re: [PATCH 3/3] ANDROID: binder: fix proc->tsk check.
To: Martijn Coenen <maco@android.com>
Cc: Greg KH <gregkh@linuxfoundation.org>, Todd Kjos <tkjos@google.com>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        Amit Pundir <amit.pundir@linaro.org>,
        lkml <linux-kernel@vger.kernel.org>, devel@driverdev.osuosl.org,
        Martijn Coenen <maco@google.com>
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On Fri, Jul 28, 2017 at 4:56 AM, Martijn Coenen <maco@android.com> wrote:
> Commit c4ea41ba195d ("binder: use group leader instead of open thread")'
> was incomplete and didn't update a check in binder_mmap(), causing all
> mmap() calls into the binder driver to fail.
>
> Signed-off-by: Martijn Coenen <maco@android.com>
> ---
>  drivers/android/binder.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index f7665c31feca..831cdd7d197d 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3362,7 +3362,7 @@ static int binder_mmap(struct file *filp, struct vm_area_struct *vma)
>         const char *failure_string;
>         struct binder_buffer *buffer;
>
> -       if (proc->tsk != current)
> +       if (proc->tsk != current->group_leader)
>                 return -EINVAL;
>
>         if ((vma->vm_end - vma->vm_start) > SZ_4M)

Tested-by: John Stultz <john.stultz@linaro.org>

As Amit already confirmed, this resolves the wifi and bluetooth
regression I was seeing with Android using 4.13-rc2.

Though I've not seen it show up in Linus' tree yet, so I wanted to
pester folks so it gets into 4.13-rc (its given me some slight grief
trying to bisect down a separate issue).

thanks
-john