Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH 1/1] Drivers: hv: vmbus: Fix crash handler reset of Hyper-V synic | Date | Thu, 14 Nov 2019 11:04:16 +0100 |
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Michael Kelley <mikelley@microsoft.com> writes:
> The crash handler calls hv_synic_cleanup() to shutdown the > Hyper-V synthetic interrupt controller. But if the CPU > that calls hv_synic_cleanup() has a VMbus channel interrupt > assigned to it (which is likely the case in smaller VM sizes), > hv_synic_cleanup() returns an error and the synthetic > interrupt controller isn't shutdown. While the lack of > being shutdown hasn't caused a known problem, it still > should be fixed for highest reliability. > > So directly call hv_synic_disable_regs() instead of > hv_synic_cleanup(), which ensures that the synic is always > shutdown.
Generally, when performing kdump doing as little work as possible is always preferred and hv_synic_cleanup() does too much: taking mutex, walking through channel list,...
Also, hv_synic_cleanup() was calling hv_stimer_cleanup() and we have a second redundant invocation in hv_crash_handler().
> > Signed-off-by: Michael Kelley <mikelley@microsoft.com> > --- > drivers/hv/vmbus_drv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > index 664a415..665920d 100644 > --- a/drivers/hv/vmbus_drv.c > +++ b/drivers/hv/vmbus_drv.c > @@ -2305,7 +2305,7 @@ static void hv_crash_handler(struct pt_regs *regs) > vmbus_connection.conn_state = DISCONNECTED; > cpu = smp_processor_id(); > hv_stimer_cleanup(cpu); > - hv_synic_cleanup(cpu); > + hv_synic_disable_regs(cpu); > hyperv_cleanup(); > };
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
-- Vitaly
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