diff options
| author | Mike Larkin <mlarkin@cvs.openbsd.org> | 2018-06-22 05:21:46 +0000 |
|---|---|---|
| committer | Mike Larkin <mlarkin@cvs.openbsd.org> | 2018-06-22 05:21:46 +0000 |
| commit | 5f41f07ca4d00f62825a3341c9646010be9cc250 (patch) | |
| tree | 7f6c9f515f8bf9cdd3fd313804b8b2155d42344e /sys/arch/amd64 | |
| parent | 05d3e7c36a1ea8debb46894a625a8dd363e66427 (diff) | |
vmm(4): Be more careful when tearing down VMs, to avoid a possible race
against the VM list.
Diffstat (limited to 'sys/arch/amd64')
| -rw-r--r-- | sys/arch/amd64/amd64/vmm.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/sys/arch/amd64/amd64/vmm.c b/sys/arch/amd64/amd64/vmm.c index 2e3348210a3..7ef82f90a76 100644 --- a/sys/arch/amd64/amd64/vmm.c +++ b/sys/arch/amd64/amd64/vmm.c @@ -1,4 +1,4 @@ -/* $OpenBSD: vmm.c,v 1.201 2018/06/21 05:41:54 kevlo Exp $ */ +/* $OpenBSD: vmm.c,v 1.202 2018/06/22 05:21:45 mlarkin Exp $ */ /* * Copyright (c) 2014 Mike Larkin <mlarkin@openbsd.org> * @@ -3268,8 +3268,10 @@ vm_teardown(struct vm *vm) vm_impl_deinit(vm); /* teardown guest vmspace */ - if (vm->vm_map != NULL) + if (vm->vm_map != NULL) { uvm_map_deallocate(vm->vm_map); + vm->vm_map = NULL; + } vmm_softc->vm_ct--; if (vmm_softc->vm_ct < 1) @@ -3626,7 +3628,7 @@ vm_terminate(struct vm_terminate_params *vtp) /* * Find desired VM */ - rw_enter_read(&vmm_softc->vm_lock); + rw_enter_write(&vmm_softc->vm_lock); error = vm_find(vtp->vtp_vm_id, &vm); if (error == 0) { @@ -3644,19 +3646,17 @@ vm_terminate(struct vm_terminate_params *vtp) old, next)); } rw_exit_read(&vm->vm_vcpu_lock); - } - rw_exit_read(&vmm_softc->vm_lock); - - if (error != 0) + } else { + rw_exit_write(&vmm_softc->vm_lock); return (error); + } - /* XXX possible race here two threads terminating the same vm? */ - rw_enter_write(&vmm_softc->vm_lock); SLIST_REMOVE(&vmm_softc->vm_list, vm, vm, vm_link); - rw_exit_write(&vmm_softc->vm_lock); if (vm->vm_vcpus_running == 0) vm_teardown(vm); + rw_exit_write(&vmm_softc->vm_lock); + return (0); } |