Merge branch 'perf/urgent' into perf/core, to resolve conflict and to prepare for new patches

Conflicts:
	arch/x86/kernel/traps.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/kernel/kexec.c b/kernel/kexec.c
index c8380ad203b..28c57069ef6 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -1683,6 +1683,14 @@ int kernel_kexec(void)
 		kexec_in_progress = true;
 		kernel_restart_prepare(NULL);
 		migrate_to_reboot_cpu();
+
+		/*
+		 * migrate_to_reboot_cpu() disables CPU hotplug assuming that
+		 * no further code needs to use CPU hotplug (which is true in
+		 * the reboot case). However, the kexec path depends on using
+		 * CPU hotplug again; so re-enable it here.
+		 */
+		cpu_hotplug_enable();
 		printk(KERN_EMERG "Starting new kernel\n");
 		machine_shutdown();
 	}