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From: Wu Fengguang <fengguang.wu@intel.com>
To: "Antonino A. Daplas" <adaplas@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-fbdev@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: [RFC] fbmem: reset file->private_data on failed fb_open()
Date: Thu, 09 Jun 2011 03:06:28 +0000	[thread overview]
Message-ID: <20110609030628.GA10233@localhost> (raw)

I wrote this when looking at NULL dereference bug
https://bugzilla.kernel.org/show_bug.cgi?id\x18912

Will it help by clearing private_data? I have no idea at all, because
for regular files, ->release won't be called on failed ->open. Just in
case there are some exceptions in fbmem...

---
 drivers/video/fbmem.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- linux-next.orig/drivers/video/fbmem.c	2011-06-09 10:36:06.000000000 +0800
+++ linux-next/drivers/video/fbmem.c	2011-06-09 10:39:30.000000000 +0800
@@ -1424,26 +1424,28 @@ __releases(&info->lock)
 	file->private_data = info;
 	if (info->fbops->fb_open) {
 		res = info->fbops->fb_open(info,1);
 		if (res)
 			module_put(info->fbops->owner);
 	}
 #ifdef CONFIG_FB_DEFERRED_IO
 	if (info->fbdefio)
 		fb_deferred_io_open(info, inode, file);
 #endif
 out:
 	mutex_unlock(&info->lock);
-	if (res)
+	if (res) {
+		file->private_data = NULL;
 		put_fb_info(info);
+	}
 	return res;
 }
 
 static int 
 fb_release(struct inode *inode, struct file *file)
 __acquires(&info->lock)
 __releases(&info->lock)
 {
 	struct fb_info * const info = file->private_data;
 
 	mutex_lock(&info->lock);
 	if (info->fbops->fb_release)

WARNING: multiple messages have this Message-ID (diff)
From: Wu Fengguang <fengguang.wu@intel.com>
To: "Antonino A. Daplas" <adaplas@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-fbdev@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
Subject: [RFC] fbmem: reset file->private_data on failed fb_open()
Date: Thu, 9 Jun 2011 11:06:28 +0800	[thread overview]
Message-ID: <20110609030628.GA10233@localhost> (raw)

I wrote this when looking at NULL dereference bug
https://bugzilla.kernel.org/show_bug.cgi?id=18912

Will it help by clearing private_data? I have no idea at all, because
for regular files, ->release won't be called on failed ->open. Just in
case there are some exceptions in fbmem...

---
 drivers/video/fbmem.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- linux-next.orig/drivers/video/fbmem.c	2011-06-09 10:36:06.000000000 +0800
+++ linux-next/drivers/video/fbmem.c	2011-06-09 10:39:30.000000000 +0800
@@ -1424,26 +1424,28 @@ __releases(&info->lock)
 	file->private_data = info;
 	if (info->fbops->fb_open) {
 		res = info->fbops->fb_open(info,1);
 		if (res)
 			module_put(info->fbops->owner);
 	}
 #ifdef CONFIG_FB_DEFERRED_IO
 	if (info->fbdefio)
 		fb_deferred_io_open(info, inode, file);
 #endif
 out:
 	mutex_unlock(&info->lock);
-	if (res)
+	if (res) {
+		file->private_data = NULL;
 		put_fb_info(info);
+	}
 	return res;
 }
 
 static int 
 fb_release(struct inode *inode, struct file *file)
 __acquires(&info->lock)
 __releases(&info->lock)
 {
 	struct fb_info * const info = file->private_data;
 
 	mutex_lock(&info->lock);
 	if (info->fbops->fb_release)

             reply	other threads:[~2011-06-09  3:06 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-09  3:06 Wu Fengguang [this message]
2011-06-09  3:06 ` [RFC] fbmem: reset file->private_data on failed fb_open() Wu Fengguang
2011-06-09  6:10 ` Bruno Prémont
2011-06-09  6:10   ` Bruno Prémont
2011-06-09  6:38   ` Wu Fengguang
2011-06-09  6:38     ` Wu Fengguang

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