[RFC][PATCHv2 6/8] kexec: switch to printk.emergency mode in unsafe places

[Sergey Senozhatsky]

Switch to printk emergency mode in kernel_kexec(), this
lets us to immediately flush pending kernel message to
the console and to avoid potentially unsafe calls into
the scheduler.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
 kernel/kexec_core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index bfe62d5b3872..5684ba36ec15 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -1496,6 +1496,8 @@ int kernel_kexec(void)
 		goto Unlock;
 	}
 
+	printk_emergency_begin();
+
 #ifdef CONFIG_KEXEC_JUMP
 	if (kexec_image->preserve_context) {
 		lock_system_sleep();
@@ -1565,6 +1567,8 @@ int kernel_kexec(void)
 	}
 #endif
 
+	printk_emergency_end();
+
  Unlock:
 	mutex_unlock(&kexec_mutex);
 	return error;
-- 
2.12.2