[PATCH 3.10 01/23] ARM: 7815/1: kexec: offline non panic CPUs on Kdump panic

From: Greg Kroah-Hartman
Date: Thu Jan 23 2014 - 13:46:43 EST

3.10-stable review patch. If anyone has any objections, please let me know.


From: Vijaya Kumar K <vijay.kilari@xxxxxxxxx>

commit 4f9b4fb7a2091eec339413a460b1665758401828 upstream.

In case of normal kexec kernel load, all cpu's are offlined
before calling machine_kexec().But in case crash panic cpus
are relaxed in machine_crash_nonpanic_core() SMP function
but not offlined.

When crash kernel is loaded with kexec and on panic trigger
machine_kexec() checks for number of cpus online.
If more than one cpu is online machine_kexec() fails to load
with below error

kexec: error: multiple CPUs still online

In machine_crash_nonpanic_core() SMP function, offline CPU
before cpu_relax

Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Stephen Warren <swarren@xxxxxxxxxxxxx>
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
Cc: l00221744 <sdu.liu@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

arch/arm/kernel/machine_kexec.c | 1 +
1 file changed, 1 insertion(+)

--- a/arch/arm/kernel/machine_kexec.c
+++ b/arch/arm/kernel/machine_kexec.c
@@ -73,6 +73,7 @@ void machine_crash_nonpanic_core(void *u
crash_save_cpu(&regs, smp_processor_id());

+ set_cpu_online(smp_processor_id(), false);
while (1)

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