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authorOliver Neukum <oneukum@suse.de>2007-02-08 15:42:53 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2007-02-16 15:32:19 -0800
commit5b06470816fb5e658e81db2a55b530ff2ba711c9 (patch)
treef43ea87c2808916a5f9f27238d82fd4481383cf2 /drivers/usb
parent57e4f041bfffa191a318dab44eb991d79a6a9d5c (diff)
USB: fix autosuspend race in skeleton driver
as the skeleton driver was made ready for autosuspend a race condition was introduced. The reference to get device must be gotten before the autosuspend counter is upped, as this operation may sleep, dropping BKL. Dropping BKL means that the pointer to the device may become invalid. Here's the fix. Signed-off-by: Oliver Neukum <oneukum@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
-rw-r--r--drivers/usb/usb-skeleton.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c
index 296b091cf168..46929a1b6f24 100644
--- a/drivers/usb/usb-skeleton.c
+++ b/drivers/usb/usb-skeleton.c
@@ -90,13 +90,15 @@ static int skel_open(struct inode *inode, struct file *file)
goto exit;
}
+ /* increment our usage count for the device */
+ kref_get(&dev->kref);
+
/* prevent the device from being autosuspended */
retval = usb_autopm_get_interface(interface);
- if (retval)
+ if (retval) {
+ kref_put(&dev->kref, skel_delete);
goto exit;
-
- /* increment our usage count for the device */
- kref_get(&dev->kref);
+ }
/* save our object in the file's private structure */
file->private_data = dev;