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From: Russell King <rmk@arm.linux.org.uk>
To: Pavel Machek <pavel@ucw.cz>
Cc: David Woodhouse <dwmw2@infradead.org>, linux-kernel@vger.kernel.org
Subject: Re: JFFS2 swsusp / signal cleanup.
Date: Sun, 5 Oct 2003 17:19:16 +0100	[thread overview]
Message-ID: <20031005171916.B21478@flint.arm.linux.org.uk> (raw)
In-Reply-To: <20031005161155.GA753@elf.ucw.cz>; from pavel@ucw.cz on Sun, Oct 05, 2003 at 06:11:55PM +0200

On Sun, Oct 05, 2003 at 06:11:55PM +0200, Pavel Machek wrote:
> Is flush_signals() really so stupid to do? Goal was to make
> modifications to code as simple as possible, and as most pieces do not
> expect to be interrupted, pretending signal never happened seems like
> good idea...

What if that signal was necessary for the operation of the thread, and
dropping it would cause a problem?

Since you're effectively using signal handling to cause a false pending
signal indication, surely the correct cleanup is to re-calculate the
pending signal indication.  That way, we won't be throwing away signals.

I'm also wondering if there could be a problem with (ab)using TASK_STOPPED
here - could a stopped task be woken prematurely and thereby sent spinning
in refrigerator() by a non-stopped process sending a SIGCONT at just the
right time?

Maybe we want a TASK_FROZEN state to describe the "frozen, may not be woken
by anything except thawing" state?

-- 
Russell King (rmk@arm.linux.org.uk)	http://www.arm.linux.org.uk/personal/
      Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
      maintainer of:  2.6 PCMCIA      - http://pcmcia.arm.linux.org.uk/
                      2.6 Serial core

  reply	other threads:[~2003-10-05 16:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-10-04 11:25 JFFS2 swsusp / signal cleanup David Woodhouse
2003-10-05 16:11 ` Pavel Machek
2003-10-05 16:19   ` Russell King [this message]
2003-10-05 19:13     ` Pavel Machek
2003-10-05 20:07       ` David Woodhouse
2003-10-09  0:23         ` [pm] " Pavel Machek
2003-10-09  0:29           ` David Woodhouse
2003-10-09  9:24             ` Pavel Machek

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