From: Oleg Nesterov <oleg@redhat.com>
To: Greg KH <gregkh@suse.de>
Cc: Tejun Heo <htejun@gmail.com>, Luke Macken <lmacken@redhat.com>,
stable@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH stable-3.0] ptrace: don't clear GROUP_STOP_SIGMASK on double-stop
Date: Mon, 26 Sep 2011 19:07:44 +0200 [thread overview]
Message-ID: <20110926170744.GA16944@redhat.com> (raw)
In-Reply-To: <20110926170632.GA16936@redhat.com>
On 09/26, Oleg Nesterov wrote:
>
> 1. Luke Macken triggered WARN_ON(!(group_stop & GROUP_STOP_SIGMASK))
> in do_signal_stop().
>
> This is because do_signal_stop() clears GROUP_STOP_SIGMASK part
> unconditionally but doesn't update it if task_is_stopped().
>
> 2. Looking at this problem I noticed that WARN_ON_ONCE(!ptrace) is
> not right, a stopped-but-resumed tracee can clone the untraced
> thread in the SIGNAL_STOP_STOPPED group, the new thread can start
> another group-stop.
>
> Remove this warning, we need more fixes to make it true.
Tejun, 3.1 has similar problems. I'll write another email...
Oleg.
next prev parent reply other threads:[~2011-09-26 17:34 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-26 17:06 [PATCH stable-3.0] ptrace: don't clear GROUP_STOP_SIGMASK on double-stop Oleg Nesterov
2011-09-26 17:07 ` Oleg Nesterov [this message]
2011-09-26 22:15 ` Greg KH
2011-09-27 12:54 ` Oleg Nesterov
2011-10-19 23:00 ` Greg KH
2011-10-20 14:47 ` Oleg Nesterov
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