Messages in this thread Patch in this message | | | From | Julien Brunel <> | Subject | [PATCH] drivers/usb/misc: Use an IS_ERR test rather than a NULL test | Date | Mon, 1 Sep 2008 10:57:27 +0200 |
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From: Julien Brunel <brunel@diku.dk>
In case of error, the function backlight_device_register returns an ERR pointer, but never returns a NULL pointer. So a NULL test that may come after a call to this function should be strengthened by an IS_ERR test.
The semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/)
// <smpl> @match_bad_null_test@ expression x, E; statement S1,S2; @@ x = backlight_device_register(...) ... when != x = E * if (x != NULL) S1 else S2 // </smpl>
Signed-off-by: Julien Brunel <brunel@diku.dk> Signed-off-by: Julia Lawall <julia@diku.dk>
--- drivers/usb/misc/appledisplay.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff -u -p a/drivers/usb/misc/appledisplay.c b/drivers/usb/misc/appledisplay.c --- a/drivers/usb/misc/appledisplay.c +++ b/drivers/usb/misc/appledisplay.c @@ -314,7 +314,7 @@ error: pdata->urbdata, pdata->urb->transfer_dma); usb_free_urb(pdata->urb); } - if (pdata->bd) + if (pdata->bd && !IS_ERR(pdata->bd)) backlight_device_unregister(pdata->bd); kfree(pdata->msgdata); }
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