KVM: don't use anon_inode_getfd() before possible failures

Once anon_inode_getfd() has succeeded, it's impossible to undo
in a clean way and no, sys_close() is not usable in such cases.
Use anon_inode_getfile() and get_unused_fd_flags() to get struct file
and descriptor and do *not* install the file into the descriptor table
until after the last possible failure exit.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Al Viro 2016-07-14 18:54:17 +02:00 committed by Paolo Bonzini
parent 7964218c7d
commit 506cfba9e7

View File

@ -3050,6 +3050,7 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
{
int r;
struct kvm *kvm;
struct file *file;
kvm = kvm_create_vm(type);
if (IS_ERR(kvm))
@ -3061,17 +3062,25 @@ static int kvm_dev_ioctl_create_vm(unsigned long type)
return r;
}
#endif
r = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, O_RDWR | O_CLOEXEC);
r = get_unused_fd_flags(O_CLOEXEC);
if (r < 0) {
kvm_put_kvm(kvm);
return r;
}
file = anon_inode_getfile("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
if (IS_ERR(file)) {
put_unused_fd(r);
kvm_put_kvm(kvm);
return PTR_ERR(file);
}
if (kvm_create_vm_debugfs(kvm, r) < 0) {
kvm_put_kvm(kvm);
put_unused_fd(r);
fput(file);
return -ENOMEM;
}
fd_install(r, file);
return r;
}