From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Problem with cpu_rest() change
Date: Mon, 24 Jan 2005 13:40:42 +1100 [thread overview]
Message-ID: <1106534442.5272.10.camel@gaston> (raw)
Hi Ingo !
Could you explain me precisely what is the race you are fixing by adding
local_irq_disable() to rest_init() ?
This patch is causing lockups on boot on various ppc machines. I think
i've found at least one possible reason for that in the ppc cpu_idle()
code, which may not re-enable interrupts in some cases when
need_resched() is not set, assuming they were enabled on entry. However,
I'm wondering precisely what exact race you are trying to fix as my fix
would cause IRQs to be re-enabled before the call to schedule() when
need_resched() is not set, which goes against the comment you added to
rest_init() about letting them be re-enable by schedule() itself...
Ben.
next reply other threads:[~2005-01-24 2:40 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-24 2:40 Benjamin Herrenschmidt [this message]
2005-01-25 9:01 ` Problem with cpu_rest() change Ingo Molnar
2005-01-25 23:49 ` Benjamin Herrenschmidt
2005-01-26 5:45 ` Kumar Gala
2005-01-26 13:44 ` Benjamin Herrenschmidt
2005-01-26 14:10 ` Kumar Gala
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