[PATCH AUTOSEL 4.19 030/101] powerpc/pseries/mobility: prevent cpu hotplug during DT update
From: Sasha Levin
Date: Fri Jul 19 2019 - 00:08:45 EST
From: Nathan Lynch <nathanl@xxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxx>
Reviewed-by: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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 f0e30dc94988..7b60fcf04dc4 100644
@@ -9,6 +9,7 @@
* 2 as published by the Free Software Foundation.
@@ -344,11 +345,19 @@ void post_mobility_fixup(void)
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.
rc = pseries_devicetree_update(MIGRATION_SCOPE);
printk(KERN_ERR "Post-mobility device tree update "
"failed: %d\n", rc);
/* Possibly switch to a new RFI flush type */