adb: fix deadlock.
libusb hotplug callbacks are called with the libusb lock taken, and we
call into libusb with our local mutex, so we need to enforce an ordering
between the two. Instead of calling device_connected or
device_disconnected directly, enqueue them onto the main thread.
Bug: http://b/62200735
Test: manually hotplugged a device
Change-Id: Ic5d55db83b47f4bb60f124ce94ddfe06f5f1a0c6
diff --git a/client/usb_libusb.cpp b/client/usb_libusb.cpp
index fc32469..9477c56 100644
--- a/client/usb_libusb.cpp
+++ b/client/usb_libusb.cpp
@@ -427,11 +427,15 @@
static int hotplug_callback(libusb_context*, libusb_device* device, libusb_hotplug_event event,
void*) {
- if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED) {
- device_connected(device);
- } else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT) {
- device_disconnected(device);
- }
+ // We're called with the libusb lock taken. Call these on the main thread outside of this
+ // function so that the usb_handle mutex is always taken before the libusb mutex.
+ fdevent_run_on_main_thread([device, event]() {
+ if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_ARRIVED) {
+ device_connected(device);
+ } else if (event == LIBUSB_HOTPLUG_EVENT_DEVICE_LEFT) {
+ device_disconnected(device);
+ }
+ });
return 0;
}
