From 534775cfaed3a73a6ea4eee957545fcecdfd5f4c Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Sun, 3 Jun 2007 13:50:41 -0700
Subject: [PATCH] --- yaml --- r: 57318 b: refs/heads/master c:
 78ae87c3cd723c8a8dcd67d4e4cbc6d63671c108 h: refs/heads/master v: v3

---
 [refs]           |  2 +-
 trunk/fs/ioctl.c | 14 +++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 129feb2f0e5a..6d12450c4cc5 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 4c738480d21a190e3d99c7ce985ab9484f373a3c
+refs/heads/master: 78ae87c3cd723c8a8dcd67d4e4cbc6d63671c108
diff --git a/trunk/fs/ioctl.c b/trunk/fs/ioctl.c
index 479c1038ed4a..8c90cbc903fa 100644
--- a/trunk/fs/ioctl.c
+++ b/trunk/fs/ioctl.c
@@ -12,6 +12,7 @@
 #include <linux/fs.h>
 #include <linux/security.h>
 #include <linux/module.h>
+#include <linux/kallsyms.h>
 
 #include <asm/uaccess.h>
 #include <asm/ioctls.h>
@@ -20,6 +21,7 @@ static long do_ioctl(struct file *filp, unsigned int cmd,
 		unsigned long arg)
 {
 	int error = -ENOTTY;
+	void *f;
 
 	if (!filp->f_op)
 		goto out;
@@ -29,10 +31,16 @@ static long do_ioctl(struct file *filp, unsigned int cmd,
 		if (error == -ENOIOCTLCMD)
 			error = -EINVAL;
 		goto out;
-	} else if (filp->f_op->ioctl) {
+	} else if ((f = filp->f_op->ioctl)) {
 		lock_kernel();
-		error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
-					  filp, cmd, arg);
+		if (!filp->f_op->ioctl) {
+			printk("%s: ioctl %p disappeared\n", __FUNCTION__, f);
+			print_symbol("symbol: %s\n", (unsigned long)f);
+			dump_stack();
+		} else {
+			error = filp->f_op->ioctl(filp->f_path.dentry->d_inode,
+						  filp, cmd, arg);
+		}
 		unlock_kernel();
 	}