Re: [PATCH 02/37] binder: use group leader instead of open thread

[John Stultz <john.stultz@linaro.org>]

On Mon, Jul 24, 2017 at 2:23 PM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Mon, Jul 24, 2017 at 02:00:45PM -0700, John Stultz wrote:
>> On Thu, Jun 29, 2017 at 12:01 PM, Todd Kjos <tkjos@android.com> wrote:
>> > The binder allocator assumes that the thread that
>> > called binder_open will never die for the lifetime of
>> > that proc. That thread is normally the group_leader,
>> > however it may not be. Use the group_leader instead
>> > of current.
>> >
>> > Signed-off-by: Todd Kjos <tkjos@google.com>
>> > ---
>> >  drivers/android/binder.c | 4 ++--
>> >  1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/android/binder.c b/drivers/android/binder.c
>> > index 157bd3e49ff4..9393924ae8e8 100644
>> > --- a/drivers/android/binder.c
>> > +++ b/drivers/android/binder.c
>> > @@ -3460,8 +3460,8 @@ static int binder_open(struct inode *nodp, struct file *filp)
>> >         proc = kzalloc(sizeof(*proc), GFP_KERNEL);
>> >         if (proc == NULL)
>> >                 return -ENOMEM;
>> > -       get_task_struct(current);
>> > -       proc->tsk = current;
>> > +       get_task_struct(current->group_leader);
>> > +       proc->tsk = current->group_leader;
>> >         INIT_LIST_HEAD(&proc->todo);
>> >         init_waitqueue_head(&proc->wait);
>> >         proc->default_priority = task_nice(current);
>> > --
>>
>> So this patch landed in 4.13-rc2 (c4ea41ba195d), and seems to be
>> causing a regression for me w/ HiKey. With it, I'm getting crashes
>> with the bluetooth and wifi HALs.  Reverting this patch seems to
>> resolve the issue
>>
>> I suspect some other dependency from the original patchset is missing?
>
> If you use linux-next (or all of the patches in this series), does the
> problem go away?

I had tested awhile back the entire set from Todd, and didn't see this issue.

I'll try to find some time to give -next a spin, but it might not be today.

thanks
-john