The Copy-VMFile cmdlet on the host may fail because the guest fcopy driver state machine gets out of sync. This happens because the ->state and ->context variables are accessed by the main thread and from interrupt context. If an interrupt happens between fcopy_respond_to_host and hv_poll_channel in fcopy_write, then hv_fcopy_onchannelcallback called from that interrupt sees still state HVUTIL_USERSPACE_RECV. It updates the context, but fcopy_write will not notice that update and hv_poll_channel gets called with an empty context. As a result hv_fcopy_daemon gets no more data. After a timeout Copy-VMFile fails with timeout. In my initial testing for a fix I put a "mb()" after the last .state change in fcopy_write. But this series implementes read/write memory barriers as needed. Let me know if this is overdoing things. Olaf Olaf Hering (4): hv: add helpers to handle hv_util device state hv: fcopy: use wrapper to propate state hv: kvp: use wrapper to propate state hv: vss: use wrapper to propate state drivers/hv/hv_fcopy.c | 36 ++++++++++++++++++++---------------- drivers/hv/hv_kvp.c | 38 +++++++++++++++++++++----------------- drivers/hv/hv_snapshot.c | 37 ++++++++++++++++++++----------------- drivers/hv/hyperv_vmbus.h | 12 ++++++++++++ 4 files changed, 73 insertions(+), 50 deletions(-) _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
