[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20190729190751.252069499@linuxfoundation.org>
Date: Mon, 29 Jul 2019 21:20:58 +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, Nathan Lynch <nathanl@...ux.ibm.com>,
"Gautham R. Shenoy" <ego@...ux.vnet.ibm.com>,
Michael Ellerman <mpe@...erman.id.au>,
Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.2 062/215] powerpc/pseries/mobility: prevent cpu hotplug during DT update
[ Upstream commit e59a175faa8df9d674247946f2a5a9c29c835725 ]
CPU online/offline code paths are sensitive to parts of the device
tree (various cpu node properties, cache nodes) that can be changed as
a result of a migration.
Prevent CPU hotplug while the device tree potentially is inconsistent.
Fixes: 410bccf97881 ("powerpc/pseries: Partition migration in the kernel")
Signed-off-by: Nathan Lynch <nathanl@...ux.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@...ux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
arch/powerpc/platforms/pseries/mobility.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
index 0c48c8964783..50e7aee3c7f3 100644
--- a/arch/powerpc/platforms/pseries/mobility.c
+++ b/arch/powerpc/platforms/pseries/mobility.c
@@ -6,6 +6,7 @@
* Copyright (C) 2010 IBM Corporation
*/
+#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/smp.h>
@@ -335,11 +336,19 @@ void post_mobility_fixup(void)
if (rc)
printk(KERN_ERR "Post-mobility activate-fw failed: %d\n", rc);
+ /*
+ * We don't want CPUs to go online/offline while the device
+ * tree is being updated.
+ */
+ cpus_read_lock();
+
rc = pseries_devicetree_update(MIGRATION_SCOPE);
if (rc)
printk(KERN_ERR "Post-mobility device tree update "
"failed: %d\n", rc);
+ cpus_read_unlock();
+
/* Possibly switch to a new RFI flush type */
pseries_setup_rfi_flush();
--
2.20.1
Powered by blists - more mailing lists