From: Julia Lawall <julia@diku.dk>
Date: Mon, 12 May 2008 21:02:16 +0000 (-0700)
Subject: drivers/video/pnx4008: eliminate double free
X-Git-Tag: v2.6.26-rc3~94
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a6278e5e4bce72ace681ae3cf48209fb63a5420;p=linux-2.6

drivers/video/pnx4008: eliminate double free

The function framebuffer_release just calls kfree, so calling kfree
subsequently on the same argument represents a double free.  The comments with
the definition of framebuffer_release in drivers/video/fbsysfs.c suggest that
a more elaborate definition of this function is planned, such that the
splitting up of framebuffer_release and kfree as done in the second instance
might someday make sense, but it does not make sense now.

This was found using the following semantic match.
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@
expression E;
@@

* kfree(E);
...
* framebuffer_release(E);

@@
expression E;
@@

* framebuffer_release(E);
...
* kfree(E);
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Grigory Tolstolytkin <gtolstolytkin@ru.mvista.com>
Cc: Antonino Daplas <adaplas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/drivers/video/pnx4008/pnxrgbfb.c b/drivers/video/pnx4008/pnxrgbfb.c
index 685761a073..4db6b48a87 100644
--- a/drivers/video/pnx4008/pnxrgbfb.c
+++ b/drivers/video/pnx4008/pnxrgbfb.c
@@ -100,7 +100,6 @@ static int rgbfb_remove(struct platform_device *pdev)
 		fb_dealloc_cmap(&info->cmap);
 		framebuffer_release(info);
 		platform_set_drvdata(pdev, NULL);
-		kfree(info);
 	}
 
 	pnx4008_free_dum_channel(channel_owned, pdev->id);
@@ -168,23 +167,21 @@ static int __devinit rgbfb_probe(struct platform_device *pdev)
 
 	ret = fb_alloc_cmap(&info->cmap, 256, 0);
 	if (ret < 0)
-		goto err2;
+		goto err1;
 
 	ret = register_framebuffer(info);
 	if (ret < 0)
-		goto err3;
+		goto err2;
 	platform_set_drvdata(pdev, info);
 
 	return 0;
 
-err3:
-	fb_dealloc_cmap(&info->cmap);
 err2:
-	framebuffer_release(info);
+	fb_dealloc_cmap(&info->cmap);
 err1:
 	pnx4008_free_dum_channel(channel_owned, pdev->id);
 err0:
-	kfree(info);
+	framebuffer_release(info);
 err:
 	return ret;
 }