From: Dexuan Cui decui@microsoft.com
[ Upstream commit 19873eec7e13fda140a0ebc75d6664e57c00bfb1 ]
After we Stop and later Start a VM that uses Accelerated Networking (NIC SR-IOV), currently the VF vmbus device's Instance GUID can change, so after vmbus_bus_resume() -> vmbus_request_offers(), vmbus_onoffer() can not find the original vmbus channel of the VF, and hence we can't complete() vmbus_connection.ready_for_resume_event in check_ready_for_resume_event(), and the VM hangs in vmbus_bus_resume() forever.
Fix the issue by adding a timeout, so the resuming can still succeed, and the saved state is not lost, and according to my test, the user can disable Accelerated Networking and then will be able to SSH into the VM for further recovery. Also prevent the VM in question from suspending again.
The host will be fixed so in future the Instance GUID will stay the same across hibernation.
Fixes: d8bd2d442bb2 ("Drivers: hv: vmbus: Resume after fixing up old primary channels") Signed-off-by: Dexuan Cui decui@microsoft.com Reviewed-by: Michael Kelley mikelley@microsoft.com Link: https://lore.kernel.org/r/20200905025555.45614-1-decui@microsoft.com Signed-off-by: Wei Liu wei.liu@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hv/vmbus_drv.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 24c38e44ed3bc..2d2568dac2a66 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -2231,7 +2231,10 @@ static int vmbus_bus_suspend(struct device *dev) if (atomic_read(&vmbus_connection.nr_chan_close_on_suspend) > 0) wait_for_completion(&vmbus_connection.ready_for_suspend_event);
- WARN_ON(atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0); + if (atomic_read(&vmbus_connection.nr_chan_fixup_on_resume) != 0) { + pr_err("Can not suspend due to a previous failed resuming\n"); + return -EBUSY; + }
mutex_lock(&vmbus_connection.channel_mutex);
@@ -2305,7 +2308,9 @@ static int vmbus_bus_resume(struct device *dev)
vmbus_request_offers();
- wait_for_completion(&vmbus_connection.ready_for_resume_event); + if (wait_for_completion_timeout( + &vmbus_connection.ready_for_resume_event, 10 * HZ) == 0) + pr_err("Some vmbus device is missing after suspending?\n");
/* Reset the event for the next suspend. */ reinit_completion(&vmbus_connection.ready_for_suspend_event);