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

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Date:	Thu, 23 Jan 2014 10:39:34 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org,
	Vijaya Kumar K <Vijaya.Kumar@...iumnetworks.com>,
	Stephen Warren <swarren@...dotorg.org>,
	Will Deacon <will.deacon@....com>,
	Russell King <rmk+kernel@....linux.org.uk>,
	l00221744 <sdu.liu@...wei.com>
Subject: [PATCH 3.10 01/23] ARM: 7815/1: kexec: offline non panic CPUs on Kdump panic

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

------------------

From: Vijaya Kumar K <vijay.kilari@...il.com>

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@...iumnetworks.com>
Acked-by: Stephen Warren <swarren@...dotorg.org>
Acked-by: Will Deacon <will.deacon@....com>
Signed-off-by: Russell King <rmk+kernel@....linux.org.uk>
Cc: l00221744 <sdu.liu@...wei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 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());
 	flush_cache_all();
 
+	set_cpu_online(smp_processor_id(), false);
 	atomic_dec(&waiting_for_crash_ipi);
 	while (1)
 		cpu_relax();


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