From 86f8ef2c4802ac9dbe0c8c1c12670bd915a13013 Mon Sep 17 00:00:00 2001 From: Tilman Schmidt Date: Sat, 11 Oct 2014 13:46:30 +0200 Subject: [PATCH] isdn/gigaset: fix usb_gigaset write_cmd result race In usb_gigaset function gigaset_write_cmd(), the length field of the command buffer structure could be cleared by the transmit tasklet before it was used for the function's return value. Fix by copying to a local variable before scheduling the tasklet. Signed-off-by: Tilman Schmidt Signed-off-by: David S. Miller --- drivers/isdn/gigaset/usb-gigaset.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/isdn/gigaset/usb-gigaset.c b/drivers/isdn/gigaset/usb-gigaset.c index 82e91ba1acd3..a8e652dac54d 100644 --- a/drivers/isdn/gigaset/usb-gigaset.c +++ b/drivers/isdn/gigaset/usb-gigaset.c @@ -497,6 +497,7 @@ static int send_cb(struct cardstate *cs, struct cmdbuf_t *cb) static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb) { unsigned long flags; + int len; gigaset_dbg_buffer(cs->mstate != MS_LOCKED ? DEBUG_TRANSCMD : DEBUG_LOCKCMD, @@ -515,10 +516,11 @@ static int gigaset_write_cmd(struct cardstate *cs, struct cmdbuf_t *cb) spin_unlock_irqrestore(&cs->cmdlock, flags); spin_lock_irqsave(&cs->lock, flags); + len = cb->len; if (cs->connected) tasklet_schedule(&cs->write_tasklet); spin_unlock_irqrestore(&cs->lock, flags); - return cb->len; + return len; } static int gigaset_write_room(struct cardstate *cs) -- 2.20.1