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| author | Peter Holik <peter@holik.at> | 2011-03-18 18:47:44 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-03-28 07:31:22 -0700 |
| commit | a390e88f47af360091497d4c8e67420e04d54fdb (patch) | |
| tree | d51a749c0735bc42f728f6a823e3cb04409a3847 | |
| parent | 25f80165d756b99ff6b707c8509f340f725e533d (diff) | |
| download | lwn-a390e88f47af360091497d4c8e67420e04d54fdb.tar.gz lwn-a390e88f47af360091497d4c8e67420e04d54fdb.zip | |
USB: uss720 fixup refcount position
commit adaa3c6342b249548ea830fe8e02aa5b45be8688 upstream.
My testprog do a lot of bitbang - after hours i got following warning and my machine lockups:
WARNING: at /build/buildd/linux-2.6.38/lib/kref.c:34
After debugging uss720 driver i discovered that the completion callback was called before
usb_submit_urb returns. The callback frees the request structure that is krefed on return by
usb_submit_urb.
Signed-off-by: Peter Holik <peter@holik.at>
Acked-by: Thomas Sailer <t.sailer@alumni.ethz.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/usb/misc/uss720.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/usb/misc/uss720.c b/drivers/usb/misc/uss720.c index 5a03b2e4c393..56b1e735a078 100644 --- a/drivers/usb/misc/uss720.c +++ b/drivers/usb/misc/uss720.c @@ -176,12 +176,11 @@ static struct uss720_async_request *submit_async_request(struct parport_uss720_p spin_lock_irqsave(&priv->asynclock, flags); list_add_tail(&rq->asynclist, &priv->asynclist); spin_unlock_irqrestore(&priv->asynclock, flags); + kref_get(&rq->ref_count); ret = usb_submit_urb(rq->urb, mem_flags); - if (!ret) { - kref_get(&rq->ref_count); + if (!ret) return rq; - } - kref_put(&rq->ref_count, destroy_async); + destroy_async(&rq->ref_count); err("submit_async_request submit_urb failed with %d", ret); return NULL; } |