3.16.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Mayank Rana mrana@codeaurora.org
commit b3207c65dfafae27e7c492cb9188c0dc0eeaf3fd upstream.
xhci_stop_device() calls xhci_queue_stop_endpoint() multiple times without checking the return value. xhci_queue_stop_endpoint() can return error if the HC is already halted or unable to queue commands. This can cause a deadlock condition as xhci_stop_device() would end up waiting indefinitely for a completion for the command that didn't get queued. Fix this by checking the return value and bailing out of xhci_stop_device() in case of error. This patch happens to fix potential memory leaks of the allocated command structures as well.
Fixes: c311e391a7ef ("xhci: rework command timeout and cancellation,") Signed-off-by: Mayank Rana mrana@codeaurora.org Signed-off-by: Jack Pham jackp@codeaurora.org Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -293,15 +293,25 @@ static int xhci_stop_device(struct xhci_ GFP_NOWAIT); if (!command) { spin_unlock_irqrestore(&xhci->lock, flags); - xhci_free_command(xhci, cmd); - return -ENOMEM; + ret = -ENOMEM; + goto cmd_cleanup; + }
+ ret = xhci_queue_stop_endpoint(xhci, command, slot_id, + i, suspend); + if (ret) { + spin_unlock_irqrestore(&xhci->lock, flags); + xhci_free_command(xhci, command); + goto cmd_cleanup; } - xhci_queue_stop_endpoint(xhci, command, slot_id, i, - suspend); } } - xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend); + ret = xhci_queue_stop_endpoint(xhci, cmd, slot_id, 0, suspend); + if (ret) { + spin_unlock_irqrestore(&xhci->lock, flags); + goto cmd_cleanup; + } + xhci_ring_cmd_db(xhci); spin_unlock_irqrestore(&xhci->lock, flags);
@@ -312,6 +322,8 @@ static int xhci_stop_device(struct xhci_ xhci_warn(xhci, "Timeout while waiting for stop endpoint command\n"); ret = -ETIME; } + +cmd_cleanup: xhci_free_command(xhci, cmd); return ret; }