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Date:   Thu, 12 Dec 2019 12:05:14 +0100
From:   Christian Brauner <christian.brauner@ubuntu.com>
To:     Oleg Nesterov <oleg@redhat.com>, qiwuchen55@gmail.com
Cc:     qiwuchen55@gmail.com, peterz@infradead.org, mingo@kernel.org,
        kernel-team@android.com, linux-kernel@vger.kernel.org,
        chenqiwu <chenqiwu@xiaomi.com>
Subject: Re: [PATCH] kernel/exit: do panic earlier to get coredump if global
 init task exit
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 <20191212095127.GA5460@redhat.com>
 <20191212100838.GB5460@redhat.com>
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On Thu, Dec 12, 2019 at 11:08:38AM +0100, Oleg Nesterov wrote:
> can't you use is_global_init() && group_dead ?

Seems reasonable.
Looks like we can move
group_dead = atomic_dec_and_test(&tsk->signal->live);
further up...

(Ideally I'd like to have a test for this to ensure that this lets you
capture a global init coredump but that might be tricky. But since you've
seem to have run into this case maybe you even have something that could
be turned into a test? (Similar to how we already have a purely opt-in
test for pstore.))

Christian