On Sat, Dec 03, 2016 at 12:34:28PM -0800, k...@exchange.microsoft.com wrote: > From: Vitaly Kuznetsov <vkuzn...@redhat.com> > > DoS protection conditions were altered in WS2016 and now it's easy to get > -EAGAIN returned from vmbus_post_msg() (e.g. when we try changing MTU on a > netvsc device in a loop). All vmbus_post_msg() callers don't retry the > operation and we usually end up with a non-functional device or crash. > > While host's DoS protection conditions are unknown to me my tests show that > it can take up to 10 seconds before the message is sent so doing udelay() > is not an option, we really need to sleep. Almost all vmbus_post_msg() > callers are ready to sleep but there is one special case: > vmbus_initiate_unload() which can be called from interrupt/NMI context and > we can't sleep there. I'm also not sure about the lonely > vmbus_send_tl_connect_request() which has no in-tree users but its external > users are most likely waiting for the host to reply so sleeping there is > also appropriate. > > Signed-off-by: Vitaly Kuznetsov <vkuzn...@redhat.com> > Signed-off-by: K. Y. Srinivasan <k...@microsoft.com>
Shouldn't this go to stable kernels so that 4.9 and earlier can work properly on WS2016? thanks, greg k-h
