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Message-ID: <4A1AE02D.5080701@gmail.com>
Date: Mon, 25 May 2009 20:15:09 +0200
From: Jiri Slaby <jirislaby@gmail.com>
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To: Oleg Nesterov <oleg@redhat.com>
CC: Andrew Morton <akpm@linux-foundation.org>, ebiederm@xmission.com,
       roland@redhat.com, linux-kernel@vger.kernel.org,
       Matthew Wilcox <matthew@wil.cx>
Subject: Re: [PATCH 1/1] signal: make group kill signal fatal
References: <1243198054-13816-1-git-send-email-jirislaby@gmail.com> <20090525000750.GA2301@redhat.com> <4A1AC5A3.9000600@gmail.com> <20090525172033.GA12586@redhat.com>
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On 05/25/2009 07:20 PM, Oleg Nesterov wrote:
> On 05/25, Jiri Slaby wrote:
>> If the poll isn't there, it works well.
> 
> Hmm. this is strange. Do you mean that if this program does
> sleep(10000) (or something else) instead of poll() above, it
> prints pend != 0 ?

No, only when there is nothing, i.e. when it directly calls close. It's
consistent with what you wrote. When there is sleep(), it works the same
as the poll case.

> And. Why do you need fatal_signal_pending() ? It is special,
> should be used by things like wait_event_killable().

I need to wait for a device to finish its work in last release, but also
want to allow user to kill the waiting by SIGKILL if he thinks the
device locked up (this is pretty usual for that particular device). If I
use wait_event_killable, I end up with this.

Well, there is a STOP ioctl and a user should catch sigterm/int/quit and
call that ioctl and bail out. But users are weird and get unkillable
processes.

Anyway thanks for the clarification.