From: Andi Kleen <ak@suse.de>
To: linux-kernel@vger.kernel.org
Subject: Raising an disabled tasklet / VC/KBD initialization bug.
Date: Mon, 4 Mar 2002 17:56:03 +0100 [thread overview]
Message-ID: <20020304175603.A17963@wotan.suse.de> (raw)
Hallo,
I just ran into the following situation on x86-64 on 2.4.17. I think
2.5 has the same problem.
For some reason vc_init executed in init order after kbd_init
(they are both indirectly called via __initcall so it can happen)
vc_init does a tasklet_schedule for the keyboard tasklet in
set_leds. The keyboard tasklet had not been enabled yet because kbd_init
didn't execute.
Result was an raised tasklet that wasn't enabled. schedule was called
and ran the softirqs. tasklet_action always tried to execute it, but
returned on the non zero count. The tasklet was still active. ksoftirqd
noticed that and executed do_softirq again -> endless loop.
For now I just removed the set_leds() call in reset_terminal to work around
it. The real fix would be either to add an mechanism to support raising
of disabled tasklets properly or make sure kbd_init and vc_init have defined
init order and the first always executes before the second.
Comments?
-Andi
next reply other threads:[~2002-03-04 16:56 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-04 16:56 Andi Kleen [this message]
2002-03-04 17:35 ` Raising an disabled tasklet / VC/KBD initialization bug James Simmons
2002-03-04 17:41 ` Alan Cox
2002-03-04 17:35 ` James Simmons
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