KVM: don't use anon_inode_getfd() before possible failures (506cfba9) · Commits · 戴 / test

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>

virt/kvm/kvm_main.c

+11 −2

Original line number	Diff line number	Diff line
		@@ -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;
		}

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