From: Oleg Nesterov <oleg@redhat.com>
To: Igor Zhbanov <i.zhbanov@omprussia.ru>
Cc: linux-trace-devel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Mutual debugging of 2 processes can stuck in unkillable stopped state
Date: Tue, 13 Apr 2021 19:17:43 +0200 [thread overview]
Message-ID: <20210413171741.GA7672@redhat.com> (raw)
In-Reply-To: <f7c84257-70a3-e482-0d3a-8ea95cbc8b62@omprussia.ru>
Hi Igor,
sorry for delay...
On 04/12, Igor Zhbanov wrote:
>
> Hi Oleg,
>
> So what is the cause of this problem?
The cause is clear. And well known ;) And again, this has almost nothing to do
with the mutual debugging.
The tracee sleeps in ptrace_stop(). You send SIGKILL. This wakes the tracee up,
it dequeues the signal, calls do_exit(), and stops again in PTRACE_EVENT_EXIT.
With SIGKILL in signal->shared_pending. This all looks as if the tracee doesn't
react to SIGKILL.
The only problem is that any change can break something which relies on the
current behaviour :/ I'll write another email on this.
Oleg.
prev parent reply other threads:[~2021-04-13 17:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-29 15:28 Mutual debugging of 2 processes can stuck in unkillable stopped state Igor Zhbanov
2021-03-29 16:49 ` Oleg Nesterov
2021-03-29 17:01 ` Igor Zhbanov
2021-03-29 17:38 ` Oleg Nesterov
2021-03-29 17:44 ` Igor Zhbanov
2021-04-12 7:25 ` Igor Zhbanov
2021-04-13 17:17 ` Oleg Nesterov [this message]
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