[PATCH] [16/50] powerpc/kdump: Fix timeout in crash_kexec_wait_realmode

Andi Kleen
2011-07-28T23:53:56Z

From: Michael Neuling <mikey@neuling.org>

[ upstream commit 63f21a56f1cc0b800a4c00349c59448f82473d19 ]

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

From: Anton Blanchard <anton@samba.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@samba.org>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: <stable@kernel.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>

Index: linux-2.6.35.y/arch/powerpc/kernel/crash.c
===================================================================
--- linux-2.6.35.y.orig/arch/powerpc/kernel/crash.c
+++ linux-2.6.35.y/arch/powerpc/kernel/crash.c
@@ -176,12 +176,8 @@ static void crash_kexec_wait_realmode(in

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);
}