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References: <20210311184629.589725-1-dualli@chromium.org> <20210311184629.589725-3-dualli@chromium.org>
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From:   Todd Kjos <tkjos@google.com>
Date:   Fri, 12 Mar 2021 16:01:11 -0800
Message-ID: <CAHRSSExs6v7OPcawg+CLdhqfMtXsXn38=mn84vMYmviM8sJjtA@mail.gmail.com>
Subject: Re: [PATCH v2 2/3] binder: use EINTR for interrupted wait for work
To:     Li Li <dualli@chromium.org>
Cc:     Li Li <dualli@google.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Christian Brauner <christian@brauner.io>,
        =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= <arve@android.com>,
        "open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Martijn Coenen <maco@google.com>,
        Hridya Valsaraju <hridya@google.com>,
        Suren Baghdasaryan <surenb@google.com>,
        "Joel Fernandes (Google)" <joel@joelfernandes.org>,
        Android Kernel Team <kernel-team@android.com>
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On Thu, Mar 11, 2021 at 10:46 AM Li Li <dualli@chromium.org> wrote:
>
> From: Marco Ballesio <balejs@google.com>
>
> when interrupted by a signal, binder_wait_for_work currently returns
> -ERESTARTSYS. This error code isn't propagated to user space, but a way
> to handle interruption due to signals must be provided to code using
> this API.
>
> Replace this instance of -ERESTARTSYS with -EINTR, which is propagated
> to user space.
>
> Test: built, booted, interrupted a worker thread within
> binder_wait_for_work
> Signed-off-by: Marco Ballesio <balejs@google.com>
> Signed-off-by: Li Li <dualli@google.com>

Acked-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 76ea558df03e..38bbf9a4ce99 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -3712,7 +3712,7 @@ static int binder_wait_for_work(struct binder_thread *thread,
>                 binder_inner_proc_lock(proc);
>                 list_del_init(&thread->waiting_thread_node);
>                 if (signal_pending(current)) {
> -                       ret = -ERESTARTSYS;
> +                       ret = -EINTR;
>                         break;
>                 }
>         }
> @@ -4855,7 +4855,7 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
>         if (thread)
>                 thread->looper_need_return = false;
>         wait_event_interruptible(binder_user_error_wait, binder_stop_on_user_error < 2);
> -       if (ret && ret != -ERESTARTSYS)
> +       if (ret && ret != -EINTR)
>                 pr_info("%d:%d ioctl %x %lx returned %d\n", proc->pid, current->pid, cmd, arg, ret);
>  err_unlocked:
>         trace_binder_ioctl_done(ret);
> --
> 2.31.0.rc2.261.g7f71774620-goog
>