From 089037905421f466c0344effe9bff1be100c0f94 Mon Sep 17 00:00:00 2001
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Date: Sat, 16 Jun 2012 21:21:51 +0800
Subject: [PATCH] --- yaml --- r: 311143 b: refs/heads/master c:
 4a77a5a06ec66ed05199b301e7c25f42f979afdc h: refs/heads/master i:   311141:
 7a9cdfd9fe36d79914b92ab540ee2b290ecdb15a   311139:
 b3c2d6aaceaab311ac6c8a7cf47eab37265c6f4c   311135:
 058752c3f0d9b931b7dcb497e88faa5cd53a1cfc v: v3

---
 [refs]                |  2 +-
 trunk/kernel/printk.c | 13 +++++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index bd07e8734565..f2a8c3a1c288 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e2ae715d66bf4becfb85eb84b7150e23cf27df30
+refs/heads/master: 4a77a5a06ec66ed05199b301e7c25f42f979afdc
diff --git a/trunk/kernel/printk.c b/trunk/kernel/printk.c
index ceb4a2f775a1..572730bd8a5c 100644
--- a/trunk/kernel/printk.c
+++ b/trunk/kernel/printk.c
@@ -414,7 +414,9 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
 	if (!user)
 		return -EBADF;
 
-	mutex_lock(&user->lock);
+	ret = mutex_lock_interruptible(&user->lock);
+	if (ret)
+		return ret;
 	raw_spin_lock(&logbuf_lock);
 	while (user->seq == log_next_seq) {
 		if (file->f_flags & O_NONBLOCK) {
@@ -976,6 +978,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
 {
 	bool clear = false;
 	static int saved_console_loglevel = -1;
+	static DEFINE_MUTEX(syslog_mutex);
 	int error;
 
 	error = check_syslog_permissions(type, from_file);
@@ -1002,11 +1005,17 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
 			error = -EFAULT;
 			goto out;
 		}
+		error = mutex_lock_interruptible(&syslog_mutex);
+		if (error)
+			goto out;
 		error = wait_event_interruptible(log_wait,
 						 syslog_seq != log_next_seq);
-		if (error)
+		if (error) {
+			mutex_unlock(&syslog_mutex);
 			goto out;
+		}
 		error = syslog_print(buf, len);
+		mutex_unlock(&syslog_mutex);
 		break;
 	/* Read/clear last kernel messages */
 	case SYSLOG_ACTION_READ_CLEAR: