From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: qiwuchen55@gmail.com, peterz@infradead.org, mingo@kernel.org,
kernel-team@android.com, linux-kernel@vger.kernel.org,
chenqiwu@xiaomi.com
Subject: Re: [PATCH v2] kernel/exit: do panic earlier to get coredump if global init task exit
Date: Tue, 17 Dec 2019 15:14:48 +0100 [thread overview]
Message-ID: <20191217141447.GA23152@redhat.com> (raw)
In-Reply-To: <20191216174410.xiqurqnqyipbuy4e@wittgenstein>
On 12/16, Christian Brauner wrote:
>
> On Mon, Dec 16, 2019 at 06:28:41PM +0100, Oleg Nesterov wrote:
> >
> > And I am worried atomic_dec_and_test() is called too early...
> >
> > Say, acct_process() can report the exit while some sub-thread sleeps
>
> Hm, I'm not following here. I might just be slow. acct_process() doesn't
> seem to report exit status and has been called after group_dead before.
Yes, but with this patch group_dead becomes true before the process is
"dead enough".
Suppose a process has 2 threads, T1, and T2.
T1 exits, decrements signal->live, and sleeps in PTRACE_EVENT_EXIT.
T2 exits, decrements signal->live, group_dead == T, it calls acct_process()
which reports the fact this process has exited. Probably not a real problem,
but still strange, this process has not exited yet, it is not even a zombie.
Oleg.
prev parent reply other threads:[~2019-12-17 14:15 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-16 3:18 [PATCH v2] kernel/exit: do panic earlier to get coredump if global init task exit qiwuchen55
2019-12-16 10:27 ` Christian Brauner
2019-12-16 17:28 ` Oleg Nesterov
2019-12-16 17:44 ` Christian Brauner
2019-12-17 10:50 ` chenqiwu
2019-12-17 14:25 ` Oleg Nesterov
2019-12-17 14:56 ` chenqiwu
2019-12-17 15:23 ` Oleg Nesterov
2019-12-17 19:33 ` Peter Zijlstra
2019-12-18 8:08 ` chenqiwu
2019-12-17 14:14 ` Oleg Nesterov [this message]
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