1 files changed, 13 insertions, 1 deletions

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ca65327a6de8..4c3d18d2587e 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -68,6 +68,13 @@ int console_printk[4] = {
 };
 EXPORT_SYMBOL_GPL(console_printk);
 
+/*
+ * Divert printk() messages when there is a LITMUS^RT debug listener.
+ */
+#include <litmus/debug_trace.h>
+int trace_override = 0;
+int trace_recurse = 0;
+
 atomic_t ignore_console_lock_warning __read_mostly = ATOMIC_INIT(0);
 EXPORT_SYMBOL(ignore_console_lock_warning);
 
@@ -1916,6 +1923,11 @@ int vprintk_store(int facility, int level,
          */
         text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
 
+        /* If the LITMUS^RT tracer is active then divert printk messages. */
+        if (trace_override && !trace_recurse) {
+                TRACE("%s", text);
+        }
+
         /* mark and strip a trailing newline */
         if (text_len && text[text_len-1] == '\n') {
                 text_len--;
@@ -2967,7 +2979,7 @@ static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
 void wake_up_klogd(void)
 {
         preempt_disable();
-        if (waitqueue_active(&log_wait)) {
+        if (!trace_override && waitqueue_active(&log_wait)) {
                 this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
                 irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
         }