On Tue, Nov 10, 2020 at 09:18:33PM +0100, Andrea Parri wrote: > On Tue, Nov 10, 2020 at 07:01:18PM +0000, Chris Co wrote: > > From: Chris Co <[email protected]> > > > > When invoking kexec() on a Linux guest running on a Hyper-V host, the > > kernel panics. > > > > RIP: 0010:cpuhp_issue_call+0x137/0x140 > > Call Trace: > > __cpuhp_remove_state_cpuslocked+0x99/0x100 > > __cpuhp_remove_state+0x1c/0x30 > > hv_kexec_handler+0x23/0x30 [hv_vmbus] > > hv_machine_shutdown+0x1e/0x30 > > machine_shutdown+0x10/0x20 > > kernel_kexec+0x6d/0x96 > > __do_sys_reboot+0x1ef/0x230 > > __x64_sys_reboot+0x1d/0x20 > > do_syscall_64+0x6b/0x3d8 > > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > > > This was due to hv_synic_cleanup() callback returning -EBUSY to > > cpuhp_issue_call() when tearing down the VMBUS_CONNECT_CPU, even > > if the vmbus_connection.conn_state = DISCONNECTED. hv_synic_cleanup() > > should succeed in the case where vmbus_connection.conn_state > > is DISCONNECTED. > > > > Fix is to add an extra condition to test for > > vmbus_connection.conn_state == CONNECTED on the VMBUS_CONNECT_CPU and > > only return early if true. This way the kexec() path can still shut > > everything down while preserving the initial behavior of preventing > > CPU offlining on the VMBUS_CONNECT_CPU while the VM is running. > > > > Fixes: 8a857c55420f29 ("Drivers: hv: vmbus: Always handle the VMBus > > messages on CPU0") > > Signed-off-by: Chris Co <[email protected]> > > Cc: [email protected] > > Reviewed-by: Andrea Parri (Microsoft) <[email protected]>
Applied to hyperv-fixes. Thanks Chris and Andrea. Wei.
