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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2017-07-06 14:44:28 +0200 |
|---|---|---|
| committer | Christian Borntraeger <borntraeger@de.ibm.com> | 2017-07-07 13:00:19 +0200 |
| commit | 0e4524a5d341e719e8ee9ee7db5d58e2c5a4c10e (patch) | |
| tree | 8bbd2dce248814dd8711ded32a19a8e982dba1ae /virt | |
| parent | 1372324b328cd5dabaef5e345e37ad48c63df2a9 (diff) | |
| download | lwn-0e4524a5d341e719e8ee9ee7db5d58e2c5a4c10e.tar.gz lwn-0e4524a5d341e719e8ee9ee7db5d58e2c5a4c10e.zip | |
KVM: mark vcpu->pid pointer as rcu protected
We do use rcu to protect the pid pointer. Mark it as such and
adopt all code to use the proper access methods.
This was detected by sparse.
"virt/kvm/kvm_main.c:2248:15: error: incompatible types in comparison
expression (different address spaces)"
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
| -rw-r--r-- | virt/kvm/kvm_main.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 19f0ecb9b93e..fc2d58312fd5 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -293,7 +293,12 @@ EXPORT_SYMBOL_GPL(kvm_vcpu_init); void kvm_vcpu_uninit(struct kvm_vcpu *vcpu) { - put_pid(vcpu->pid); + /* + * no need for rcu_read_lock as VCPU_RUN is the only place that + * will change the vcpu->pid pointer and on uninit all file + * descriptors are already gone. + */ + put_pid(rcu_dereference_protected(vcpu->pid, 1)); kvm_arch_vcpu_uninit(vcpu); free_page((unsigned long)vcpu->run); } @@ -2551,13 +2556,14 @@ static long kvm_vcpu_ioctl(struct file *filp, if (r) return r; switch (ioctl) { - case KVM_RUN: + case KVM_RUN: { + struct pid *oldpid; r = -EINVAL; if (arg) goto out; - if (unlikely(vcpu->pid != current->pids[PIDTYPE_PID].pid)) { + oldpid = rcu_access_pointer(vcpu->pid); + if (unlikely(oldpid != current->pids[PIDTYPE_PID].pid)) { /* The thread running this VCPU changed. */ - struct pid *oldpid = vcpu->pid; struct pid *newpid = get_task_pid(current, PIDTYPE_PID); rcu_assign_pointer(vcpu->pid, newpid); @@ -2568,6 +2574,7 @@ static long kvm_vcpu_ioctl(struct file *filp, r = kvm_arch_vcpu_ioctl_run(vcpu, vcpu->run); trace_kvm_userspace_exit(vcpu->run->exit_reason, r); break; + } case KVM_GET_REGS: { struct kvm_regs *kvm_regs; |