linux-kernel - Re: [PATCH] tty/n_hdlc: fix __might

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Message-ID: <CAK8P3a39t3pDjL9yqS6T9JQM-nGej7gvZibhya5qkC1JDHj5tw@mail.gmail.com>
Date:   Thu, 10 Jan 2019 13:25:59 +0100
From:   Arnd Bergmann <arnd@...db.de>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Paul Fulghum <paulkf@...rogate.com>,
        "linux-kernel@...r.kernel.org Mailing List" 
        <linux-kernel@...r.kernel.org>,
        Alan Cox <alan@...rguk.ukuu.org.uk>,
        syzbot <syzbot+c244af085a0159d22879@...kaller.appspotmail.com>,
        syzkaller-bugs@...glegroups.com
Subject: Re: [PATCH] tty/n_hdlc: fix __might_sleep warning

On Thu, Jan 10, 2019 at 12:39 PM Tetsuo Handa
<penguin-kernel@...ove.sakura.ne.jp> wrote:
> On 2019/01/02 5:28, Paul Fulghum wrote:
> > Fix __might_sleep warning in tty/n_hdlc.c read due to copy_to_user call while current is TASK_INTERRUPTIBLE.
> > This is a false positive since the code path does not depend on current state remaining TASK_INTERRUPTIBLE.
> > The loop breaks out and sets TASK_RUNNING after calling copy_to_user.
> > This patch supresses the warning by setting TASK_RUNNING before calling copy_to_user.
> >
> > [1] https://syzkaller.appspot.com/bug?id=17d5de7f1fcab794cb8c40032f893f52de899324
> >
> > Signed-off-by: Paul Fulghum <paulkf@...rogate.com>
> > Reported-by: syzbot <syzbot+c244af085a0159d22879@...kaller.appspotmail.com>
> > Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
> > Cc: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
> > Cc: Arnd Bergmann <arnd@...db.de>
> > Cc: Alan Cox <alan@...rguk.ukuu.org.uk>

This version looks good to me.

Acked-by: Arnd Bergmann <arnd@...db.de>

       Arnd