From 3c7e5c572f3bac968b9a7fb64c7328b00be6ab5d Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 15 Apr 2008 13:09:54 -0700
Subject: [PATCH] --- yaml --- r: 88336 b: refs/heads/master c:
 093a07e2fdfaddab7fc7d4adc76cc569c86603d7 h: refs/heads/master v: v3

---
 [refs]                |  2 +-
 trunk/kernel/printk.c | 17 +++++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index ce2a7635f4c5..90a0b1c4f30f 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0de19a456cb59106420864927fdec152310f70b6
+refs/heads/master: 093a07e2fdfaddab7fc7d4adc76cc569c86603d7
diff --git a/trunk/kernel/printk.c b/trunk/kernel/printk.c
index c46a20a19a15..bdd4ea8c3f2b 100644
--- a/trunk/kernel/printk.c
+++ b/trunk/kernel/printk.c
@@ -643,8 +643,21 @@ static int acquire_console_semaphore_for_printk(unsigned int cpu)
 {
 	int retval = 0;
 
-	if (can_use_console(cpu))
-		retval = !try_acquire_console_sem();
+	if (!try_acquire_console_sem()) {
+		retval = 1;
+
+		/*
+		 * If we can't use the console, we need to release
+		 * the console semaphore by hand to avoid flushing
+		 * the buffer. We need to hold the console semaphore
+		 * in order to do this test safely.
+		 */
+		if (!can_use_console(cpu)) {
+			console_locked = 0;
+			up(&console_sem);
+			retval = 0;
+		}
+	}
 	printk_cpu = UINT_MAX;
 	spin_unlock(&logbuf_lock);
 	return retval;