linux-kernel - [PATCH] avr32: Fixup kprobes preemption handling.

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Date:	Fri, 1 Dec 2006 16:50:50 +0900
From:	Paul Mundt <lethal@...ux-sh.org>
To:	Haavard Skinnemoen <hskinnemoen@...el.com>
Subject: [PATCH] avr32: Fixup kprobes preemption handling.

While working on SH kprobes, I noticed that avr32 got the preemption
handling wrong in the no probe case. The idea is that upon entry of
kprobe_handler() preemption is disabled outright across the life of the
kprobe, only to be re-enabled in post_kprobe_handler().

However, in the event that the probe is never activated, there's never
any chance of hitting the post probe handler, which allows for the
current avr32 implementation to disable preemption indefinitely, as it's
currently missing a re-enable when no probe is activated.

Patch follows.

--

diff --git a/arch/avr32/kernel/kprobes.c b/arch/avr32/kernel/kprobes.c
index ca41fc1..d0abbca 100644
--- a/arch/avr32/kernel/kprobes.c
+++ b/arch/avr32/kernel/kprobes.c
@@ -154,6 +154,7 @@ ss_probe:
 	return 1;

 no_kprobe:
+	preempt_enable_no_resched();
 	return ret;
 }
-
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