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| author | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-04 15:16:52 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2020-06-04 17:00:54 +0200 |
| commit | d56f5136b01020155b6b0a29f69d924687529bee (patch) | |
| tree | 3e3036834486e7506c7293e92649b9fab3119620 /include | |
| parent | atomisp: avoid warning about unused function (diff) | |
| download | linux-d56f5136b01020155b6b0a29f69d924687529bee.tar.xz linux-d56f5136b01020155b6b0a29f69d924687529bee.zip | |
KVM: let kvm_destroy_vm_debugfs clean up vCPU debugfs directories
After commit 63d0434 ("KVM: x86: move kvm_create_vcpu_debugfs after
last failure point") we are creating the pre-vCPU debugfs files
after the creation of the vCPU file descriptor. This makes it
possible for userspace to reach kvm_vcpu_release before
kvm_create_vcpu_debugfs has finished. The vcpu->debugfs_dentry
then does not have any associated inode anymore, and this causes
a NULL-pointer dereference in debugfs_create_file.
The solution is simply to avoid removing the files; they are
cleaned up when the VM file descriptor is closed (and that must be
after KVM_CREATE_VCPU returns). We can stop storing the dentry
in struct kvm_vcpu too, because it is not needed anywhere after
kvm_create_vcpu_debugfs returns.
Reported-by: syzbot+705f4401d5a93a59b87d@syzkaller.appspotmail.com
Fixes: 63d04348371b ("KVM: x86: move kvm_create_vcpu_debugfs after last failure point")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/kvm_host.h | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index f43b59b1294c..d38d6b9c24be 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -318,7 +318,6 @@ struct kvm_vcpu { bool preempted; bool ready; struct kvm_vcpu_arch arch; - struct dentry *debugfs_dentry; }; static inline int kvm_vcpu_exiting_guest_mode(struct kvm_vcpu *vcpu) @@ -888,7 +887,7 @@ void kvm_arch_vcpu_postcreate(struct kvm_vcpu *vcpu); void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu); #ifdef __KVM_HAVE_ARCH_VCPU_DEBUGFS -void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu); +void kvm_arch_create_vcpu_debugfs(struct kvm_vcpu *vcpu, struct dentry *debugfs_dentry); #endif int kvm_arch_hardware_enable(void); |