On 02/05/2019 17:03, Dan Carpenter wrote: > Hello Cédric Le Goater, > > This is a semi-automatic email about new static checker warnings. > > The patch 2bde9b3ec8bd: "KVM: Introduce a 'release' method for KVM > devices" from Apr 18, 2019, leads to the following Smatch complaint: Already reported https://lkml.org/lkml/2019/5/1/235 > > arch/x86/kvm/../../../virt/kvm/kvm_main.c:2943 kvm_device_release() > warn: variable dereferenced before check 'dev' (see line 2941) > > arch/x86/kvm/../../../virt/kvm/kvm_main.c > 2938 static int kvm_device_release(struct inode *inode, struct file *filp) > 2939 { > 2940 struct kvm_device *dev = filp->private_data; > 2941 struct kvm *kvm = dev->kvm; > ^^^^^^^^ > Dereference. > > 2942 > 2943 if (!dev) > ^^^^ > Checked too late. > > 2944 return -ENODEV; > 2945 > 2946 if (dev->kvm != kvm) > ^^^^^^^^^^^^^^^ > What is this testing? We just set "kvm = dev->kvm;" at the start. > > 2947 return -EPERM; > 2948 > 2949 if (dev->ops->release) { > 2950 mutex_lock(&kvm->lock); > 2951 list_del(&dev->vm_node); > 2952 dev->ops->release(dev); > 2953 mutex_unlock(&kvm->lock); > 2954 } > 2955 > 2956 kvm_put_kvm(kvm); > 2957 return 0; > 2958 } > > regards, > dan carpenter > -- Alexey
