From: Kirill Korotaev <dev@sw.ru>
Date: Mon, 14 Nov 2005 00:07:30 +0000 (-0800)
Subject: [PATCH] stop_machine() vs. synchronous IPI send deadlock
X-Git-Tag: v2.6.15-rc2~156
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4557398f8cbaf9f254cff747534b4724c7f75c4f;p=pandora-kernel.git

[PATCH] stop_machine() vs. synchronous IPI send deadlock

This fixes deadlock of stop_machine() vs.  synchronous IPI send.  The
problem is that stop_machine() disables interrupts before disabling
preemption on other CPUs.  So if another CPU is preempted and then calls
something like flush_tlb_all() it will deadlock with CPU doing
stop_machine() and which can't process IPI due to disabled IRQs.

I changed stop_machine() to do the same things exactly as it does on other
CPUs, i.e.  it should disable preemption first on _all_ CPUs including
itself and only after that disable IRQs.

Signed-off-by: Kirill Korotaev <dev@sw.ru>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Andrey Savochkin" <saw@sawoct.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

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