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Message-Id: <20180528100213.970408848@linuxfoundation.org>
Date: Mon, 28 May 2018 12:01:18 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Dou Liyang <douly.fnst@...fujitsu.com>,
Samuel Neves <sneves@....uc.pt>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Peter Zijlstra <peterz@...radead.org>,
Thomas Gleixner <tglx@...utronix.de>, jgross@...e.com,
luto@...nel.org, prarit@...hat.com, vkuznets@...hat.com,
Ingo Molnar <mingo@...nel.org>,
Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.4 104/268] x86/topology: Update the cpu cores field in /proc/cpuinfo correctly across CPU hotplug operations
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Samuel Neves <sneves@....uc.pt>
[ Upstream commit 4596749339e06dc7a424fc08a15eded850ed78b7 ]
Without this fix, /proc/cpuinfo will display an incorrect amount
of CPU cores, after bringing them offline and online again, as
exemplified below:
$ cat /proc/cpuinfo | grep cores
cpu cores : 4
cpu cores : 8
cpu cores : 8
cpu cores : 20
cpu cores : 4
cpu cores : 3
cpu cores : 2
cpu cores : 2
This patch fixes this by always zeroing the booted_cores variable
upon turning off a logical CPU.
Tested-by: Dou Liyang <douly.fnst@...fujitsu.com>
Signed-off-by: Samuel Neves <sneves@....uc.pt>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: jgross@...e.com
Cc: luto@...nel.org
Cc: prarit@...hat.com
Cc: vkuznets@...hat.com
Link: http://lkml.kernel.org/r/20180221205036.5244-1-sneves@dei.uc.pt
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/kernel/smpboot.c | 1 +
1 file changed, 1 insertion(+)
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1344,6 +1344,7 @@ static void remove_siblinginfo(int cpu)
cpumask_clear(topology_core_cpumask(cpu));
c->phys_proc_id = 0;
c->cpu_core_id = 0;
+ c->booted_cores = 0;
cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
}
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