xen/x86: fix cpu hotplug

Commit dc6416f ("xen/x86: Call cpu_startup_entry(CPUHP_AP_ONLINE_IDLE) from xen_play_dead()") introduced an error leading to a stack overflow of the idle task when a cpu was brought offline/online many times: by calling cpu_startup_entry() instead of returning at the end of xen_play_dead() do_idle() would be entered again and again. Don't use cpu_startup_entry(), but cpuhp_online_idle() instead allowing to return from xen_play_dead(). Cc: <[email protected]> # 4.12 Signed-off-by: Juergen Gross <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Juergen Gross <[email protected]>
kyagi · Jul 23, 2017 · c185dde · c185dde
1 parent 29d11cf
commit c185dde
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/arch/x86/xen/smp_pv.c b/arch/x86/xen/smp_pv.c
@@ -19,6 +19,7 @@
 #include <linux/irq_work.h>
 #include <linux/tick.h>
 #include <linux/nmi.h>
+#include <linux/cpuhotplug.h>
 
 #include <asm/paravirt.h>
 #include <asm/desc.h>
@@ -413,7 +414,7 @@ static void xen_pv_play_dead(void) /* used only with HOTPLUG_CPU */
 	 */
 	tick_nohz_idle_enter();
 
-	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
+	cpuhp_online_idle(CPUHP_AP_ONLINE_IDLE);
 }
 
 #else /* !CONFIG_HOTPLUG_CPU */