1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/char/agp/frontend.c b/drivers/char/agp/frontend.c
index 857b26227d87..963eff28fa00 100644
--- a/drivers/char/agp/frontend.c
+++ b/drivers/char/agp/frontend.c
@@ -39,6 +39,7 @@
 #include <linux/mm.h>
 #include <linux/fs.h>
 #include <linux/sched.h>
+#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include "agp.h"
@@ -677,6 +678,7 @@ static int agp_open(struct inode *inode, struct file *file)
         struct agp_client *client;
         int rc = -ENXIO;
 
+        lock_kernel();
         mutex_lock(&(agp_fe.agp_mutex));
 
         if (minor != AGPGART_MINOR)
@@ -703,12 +705,14 @@ static int agp_open(struct inode *inode, struct file *file)
         agp_insert_file_private(priv);
         DBG("private=%p, client=%p", priv, client);
         mutex_unlock(&(agp_fe.agp_mutex));
+        unlock_kernel();
         return 0;
 
 err_out_nomem:
         rc = -ENOMEM;
 err_out:
         mutex_unlock(&(agp_fe.agp_mutex));
+        unlock_kernel();
         return rc;
 }