linux-kernel - [34-longterm 131/179] powerpc/kdump: Fix timeout in crash_kexec_wait

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Date:	Mon, 14 May 2012 22:13:47 -0400
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	<stable@...nel.org>, <linux-kernel@...r.kernel.org>
Subject: [34-longterm 131/179] powerpc/kdump: Fix timeout in crash_kexec_wait_realmode

From: Michael Neuling <mikey@...ling.org>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 63f21a56f1cc0b800a4c00349c59448f82473d19 upstream.

The existing code it pretty ugly.  How about we clean it up even more
like this?

From: Anton Blanchard <anton@...ba.org>

We check for timeout expiry in the outer loop, but we also need to
check it in the inner loop or we can lock up forever waiting for a
CPU to hit real mode.

Signed-off-by: Anton Blanchard <anton@...ba.org>
Signed-off-by: Michael Neuling <mikey@...ling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
 arch/powerpc/kernel/crash.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/crash.c b/arch/powerpc/kernel/crash.c
index ddf1fea..d2f619b 100644
--- a/arch/powerpc/kernel/crash.c
+++ b/arch/powerpc/kernel/crash.c
@@ -176,12 +176,8 @@ static void crash_kexec_wait_realmode(int cpu)
 
 		while (paca[i].kexec_state < KEXEC_STATE_REAL_MODE) {
 			barrier();
-			if (!cpu_possible(i)) {
+			if (!cpu_possible(i) || !cpu_online(i) || (msecs <= 0))
 				break;
-			}
-			if (!cpu_online(i)) {
-				break;
-			}
 			msecs--;
 			mdelay(1);
 		}
-- 
1.7.9.6

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