linux-kernel - Re: [PATCH 1/8] signal: Make SIGKILL during coredumps an explicit special case

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Message-ID: <CAHk-=wjZ=aFzFb0BkxVEbN3o6a53R8Gq4hHnEZVCmpDKs3_FCw@mail.gmail.com>
Date:   Tue, 11 Jan 2022 11:19:25 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     Olivier Langlois <olivier@...llion01.com>,
        Heiko Carstens <hca@...ux.ibm.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "<linux-arch@...r.kernel.org>" <linux-arch@...r.kernel.org>,
        Linux API <linux-api@...r.kernel.org>,
        Alexey Gladkov <legion@...nel.org>,
        Kyle Huey <me@...ehuey.com>, Oleg Nesterov <oleg@...hat.com>,
        Kees Cook <keescook@...omium.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Jens Axboe <axboe@...nel.dk>,
        Pavel Begunkov <asml.silence@...il.com>
Subject: Re: [PATCH 1/8] signal: Make SIGKILL during coredumps an explicit
 special case

On Tue, Jan 11, 2022 at 10:51 AM Eric W. Biederman
<ebiederm@...ssion.com> wrote:
>
> +       while ((n == -ERESTARTSYS) && test_thread_flag(TIF_NOTIFY_SIGNAL)) {
> +               tracehook_notify_signal();
> +               n = __kernel_write(file, addr, nr, &pos);
> +       }

This reads horribly wrongly to me.

That "tracehook_notify_signal()" thing *has* to be renamed before we
have anything like this that otherwise looks like "this will just loop
forever".

I'm pretty sure we've discussed that "tracehook" thing before - the
whole header file is misnamed, and most of the functions in theer are
too.

As an ugly alternative, open-code it, so that it's clear that "yup,
that clears the TIF_NOTIFY_SIGNAL flag".

             Linus