4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Mayank Rana <mrana@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxx>
Signed-off-by: Jack Pham <jackp@xxxxxxxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-hub.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -394,15 +394,25 @@ 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);
@@ -413,6 +423,8 @@ 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;
}