1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/acpi/processor_driver.c b/drivers/acpi/processor_driver.c
index bd4e5dca3ff7..a4352b88a331 100644
--- a/drivers/acpi/processor_driver.c
+++ b/drivers/acpi/processor_driver.c
@@ -852,8 +852,22 @@ static int acpi_processor_handle_eject(struct acpi_processor *pr)
         if (cpu_online(pr->id))
                 cpu_down(pr->id);
 
+        get_online_cpus();
+        /*
+         * The cpu might become online again at this point. So we check whether
+         * the cpu has been onlined or not. If the cpu became online, it means
+         * that someone wants to use the cpu. So acpi_processor_handle_eject()
+         * returns -EAGAIN.
+         */
+        if (unlikely(cpu_online(pr->id))) {
+                put_online_cpus();
+                pr_warn("Failed to remove CPU %d, because other task "
+                        "brought the CPU back online\n", pr->id);
+                return -EAGAIN;
+        }
         arch_unregister_cpu(pr->id);
         acpi_unmap_lsapic(pr->id);
+        put_online_cpus();
         return (0);
 }
 #else