2.6.38-stable review patch. If anyone has any objections, please let us know.
------------------ From: Sarah Sharp <[email protected]> commit 30f89ca021c3e584b61bc5a14eede89f74b2e826 upstream. When an endpoint ring is freed, it is either cached in a per-device ring cache, or simply freed if the ring cache is full. If the ring was added to the cache, then virt_dev->num_rings_cached is incremented. The cache is designed to hold up to 31 endpoint rings, in array indexes 0 to 30. When the device is freed (when the slot was disabled), xhci_free_virt_device() is called, it would free the cached rings in array indexes 0 to virt_dev->num_rings_cached. Unfortunately, the original code in xhci_free_or_cache_endpoint_ring() would put the first entry into the ring cache in array index 1, instead of array index 0. This was caused by the second assignment to rings_cached: rings_cached = virt_dev->num_rings_cached; if (rings_cached < XHCI_MAX_RINGS_CACHED) { virt_dev->num_rings_cached++; rings_cached = virt_dev->num_rings_cached; virt_dev->ring_cache[rings_cached] = virt_dev->eps[ep_index].ring; This meant that when the device was freed, cached rings with indexes 0 to N would be freed, and the last cached ring in index N+1 would not be freed. When the driver was unloaded, this caused interesting messages like: xhci_hcd 0000:06:00.0: dma_pool_destroy xHCI ring segments, ffff880063040000 busy This should be queued to stable kernels back to 2.6.33. Signed-off-by: Sarah Sharp <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- drivers/usb/host/xhci-mem.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -207,14 +207,13 @@ void xhci_free_or_cache_endpoint_ring(st rings_cached = virt_dev->num_rings_cached; if (rings_cached < XHCI_MAX_RINGS_CACHED) { - virt_dev->num_rings_cached++; - rings_cached = virt_dev->num_rings_cached; virt_dev->ring_cache[rings_cached] = virt_dev->eps[ep_index].ring; + virt_dev->num_rings_cached++; xhci_dbg(xhci, "Cached old ring, " "%d ring%s cached\n", - rings_cached, - (rings_cached > 1) ? "s" : ""); + virt_dev->num_rings_cached, + (virt_dev->num_rings_cached > 1) ? "s" : ""); } else { xhci_ring_free(xhci, virt_dev->eps[ep_index].ring); xhci_dbg(xhci, "Ring cache full (%d rings), " _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
