From: Ivan Delalande <colona@arista.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Dmitry Safonov <0x7f454c46@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH v2] exec: don't force_sigsegv processes with a pending fatal signal
Date: Fri, 8 Feb 2019 16:16:38 -0800 [thread overview]
Message-ID: <20190209001638.GA14025@visor> (raw)
In-Reply-To: <87pns2q2ug.fsf@xmission.com>
Hi Eric,
On Thu, Feb 07, 2019 at 11:13:59PM -0600, Eric W. Biederman wrote:
> I just noticed this. From my patch queue that I intend to send to
> Linus tomorrow. I think this change fixes your issue of getting
> the SIGSEGV instead of the already pending fatal signal.
>
> So I think this fixes your issue without any other code changes.
> Ivan can you verify that the patch below is enough?
I was having issues with just this patch applied on top of v5.0-rc5 or
the latest master: defunct processes accumulating, exiting processes
that would hang forever, and some kernel functions eating all the CPU
(setup_sigcontext, common_interrupt, __clear_user, do_signal…).
But using your user-namespace.git/for-linus worked great and I've been
running my reproducer for a few hours now without issue. I'll probably
keep it running over the week-end as it has been unreliable at times,
but it looks promising so far.
A difference I've noticed with your tree (unrelated to my issue here but
that you may want to look at) is when I run my reproducer under
strace -f, I'm now getting quite a lot of "Exit of unknown pid 12345
ignored" warnings from strace, which I've never seen with mainline.
My reproducer simply fork-exec tail processes in a loop, and tries to
sigkill them in the parent with a variable delay.
Thank you,
> diff --git a/kernel/signal.c b/kernel/signal.c
> index 9ca8e5278c8e..5424cb0006bc 100644
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -2393,6 +2393,11 @@ bool get_signal(struct ksignal *ksig)
> goto relock;
> }
>
> + /* Has this task already been marked for death? */
> + ksig->info.si_signo = signr = SIGKILL;
> + if (signal_group_exit(signal))
> + goto fatal;
> +
> for (;;) {
> struct k_sigaction *ka;
>
> @@ -2488,6 +2493,7 @@ bool get_signal(struct ksignal *ksig)
> continue;
> }
>
> + fatal:
> spin_unlock_irq(&sighand->siglock);
>
>
--
Ivan Delalande
Arista Networks
next prev parent reply other threads:[~2019-02-09 0:16 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-05 2:53 [PATCH v2] exec: don't force_sigsegv processes with a pending fatal signal Ivan Delalande
2019-02-05 21:11 ` Andrew Morton
2019-02-06 3:10 ` Ivan Delalande
2019-02-08 5:13 ` Eric W. Biederman
2019-02-09 0:16 ` Ivan Delalande [this message]
2019-02-10 17:05 ` Eric W. Biederman
2019-02-11 23:25 ` Ivan Delalande
2019-02-11 16:02 ` Oleg Nesterov
2019-02-11 17:12 ` Oleg Nesterov
2019-02-11 23:20 ` Ivan Delalande
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