This patch locks rpipe->seg_lock around the entire transfer segment
cleanup loop in wa_urb_dequeue instead of just one case of the switch
statement. This fixes a race between __wa_xfer_delayed_run and
wa_urb_dequeue where a transfer segment in the WA_SEG_DELAYED state
could be removed from the rpipe seg_list twice leading to memory
corruption. It also switches the spin_lock call to use the non-irqsave
version since the xfer->lock is already held and irqs already disabled.
Signed-off-by: Thomas Pugliese <thomas.pugliese@xxxxxxxxx>
---
drivers/usb/wusbcore/wa-xfer.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/wusbcore/wa-xfer.c b/drivers/usb/wusbcore/wa-xfer.c
index c688afa..1cd0f61 100644
--- a/drivers/usb/wusbcore/wa-xfer.c
+++ b/drivers/usb/wusbcore/wa-xfer.c
@@ -1974,6 +1974,11 @@ int wa_urb_dequeue(struct wahc *wa, struct urb *urb, int status)
goto out_unlock; /* setup(), enqueue_b() completes */
/* Ok, the xfer is in flight already, it's been setup and submitted.*/
xfer_abort_pending = __wa_xfer_abort(xfer) >= 0;
+ /*
+ * grab the rpipe->seg_lock here to prevent racing with
+ * __wa_xfer_delayed_run.
+ */
+ spin_lock(&rpipe->seg_lock);
for (cnt = 0; cnt < xfer->segs; cnt++) {
seg = xfer->seg[cnt];
pr_debug("%s: xfer id 0x%08X#%d status = %d\n",
@@ -1994,10 +1999,8 @@ int wa_urb_dequeue(struct wahc *wa, struct urb *urb, int status)
*/
seg->status = WA_SEG_ABORTED;
seg->result = -ENOENT;
- spin_lock_irqsave(&rpipe->seg_lock, flags2);
list_del(&seg->list_node);
xfer->segs_done++;
- spin_unlock_irqrestore(&rpipe->seg_lock, flags2);
break;
case WA_SEG_DONE:
case WA_SEG_ERROR:
@@ -2026,6 +2029,7 @@ int wa_urb_dequeue(struct wahc *wa, struct urb *urb, int status)
break;
}
}
+ spin_unlock(&rpipe->seg_lock);
xfer->result = urb->status; /* -ENOENT or -ECONNRESET */
done = __wa_xfer_is_done(xfer);
spin_unlock_irqrestore(&xfer->lock, flags);
--
1.8.3.2
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