Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <87efft5ncd.fsf_-_@xmission.com> <20180724032419.20231-20-ebiederm@xmission.com>
 <CA+55aFxNijeenFd6o7fg3iJFqAjdTZLaFV2=Eaqbg1fDOzx26A@mail.gmail.com>
 <874lgo5xdg.fsf@xmission.com> <CA+55aFw_CTTRTZfUf1e9yg04X_djG3q7HrCG-XqnyQorpKjaTQ@mail.gmail.com>
 <87fu084cxj.fsf@xmission.com>
In-Reply-To: <87fu084cxj.fsf@xmission.com>
From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 24 Jul 2018 13:15:21 -0700
Message-ID: <CA+55aFxUc3ttEAuRS7GKs9aTjTFw1poE80DASFSXudVQCuWpHg@mail.gmail.com>
Subject: Re: [PATCH 20/20] signal: Don't restart fork when signals come in.
To:     "Eric W. Biederman" <ebiederm@xmission.com>
Cc:     Oleg Nesterov <oleg@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Wen Yang <wen.yang99@zte.com.cn>, majiang <ma.jiang@zte.com.cn>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Jul 24, 2018 at 1:05 PM Eric W. Biederman <ebiederm@xmission.com> wrote:
>
> What I hear you asking is  moving up copy_signal copy_sighand copy_creds
> and alloc_pid, and anything else that signal delivery might depend on.

No, _just_ signal allocation.

It would still just use the special-case list to set the pending bit.
No creds, no "full task", nothing like that.

> I really want something very simple and straight forward because I don't
> see us testing or hitting this code path much in practice.  Moving this
> into the middle of fork and adding more depedencies does not seem like
> it will be that kind of straight forward.

I think your "list on the stack" was anything but straightforward,
considering how utterly broken the error handling of the patch was.

But hey., send a fixed patch and see how it looks. I think you'll end
up adding a lot of "goto signal_cleanup" cases.

          Linus