Re: [libvirt] [PATCH 2/5] Fix race condition in HAL driver startup

There is a race condition in HAL driver startup where the callback can get triggered before we have finished startup. This then causes a deadlock in the driver. * src/node_device/node_device_hal.c: RElease driver lock before registering DBus callbacks --- src/node_device/node_device_hal.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 deletions(-) diff --git a/src/node_device/node_device_hal.c b/src/node_device/node_device_hal.c index 818c7d6..918a3a9 100644 --- a/src/node_device/node_device_hal.c +++ b/src/node_device/node_device_hal.c @@ -742,6 +742,16 @@ static int halDeviceMonitorStartup(int privileged ATTRIBUTE_UNUSED) goto failure; } + /* Populate with known devices */ + driverState->privateData = hal_ctx; + + /* We need to unlock state now, since setting these callbacks cause + * a dbus RPC call, and while this call is waiting for the reply, + * a signal may already arrive, triggering the callback and thus + * requiring the lock ! + */ + nodeDeviceUnlock(driverState); + /* Register HAL event callbacks */ if (!libhal_ctx_set_device_added(hal_ctx, device_added) || !libhal_ctx_set_device_removed(hal_ctx, device_removed) || @@ -753,10 +763,6 @@ static int halDeviceMonitorStartup(int privileged ATTRIBUTE_UNUSED) goto failure; } - /* Populate with known devices */ - driverState->privateData = hal_ctx; - - nodeDeviceUnlock(driverState); udi = libhal_get_all_devices(hal_ctx, &num_devs, &err); if (udi == NULL) { VIR_ERROR0("libhal_get_all_devices failed\n");