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([2001:b07:6468:f312:59c7:c3ee:2dec:d2b4]) by smtp.gmail.com with ESMTPSA id x17sm1883439wrt.74.2020.02.17.09.15.49 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Feb 2020 09:15:49 -0800 (PST) Subject: Re: [PATCH] KVM: Add the check and free to avoid unknown errors. To: Haiwei Li , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: From: Paolo Bonzini Message-ID: <33cd2fda-f863-82be-5711-8c9e4eaa7971@redhat.com> Date: Mon, 17 Feb 2020 18:15:49 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/02/20 22:02, Haiwei Li wrote: > From: Haiwei Li > > If 'kvm_create_vm_debugfs()' fails in 'kzalloc(sizeof(*stat_data), ...)', > 'kvm_destroy_vm_debugfs()' will be called by the final fput(file) in > 'kvm_dev_ioctl_create_vm()'. Can you explain better? It is okay to pass NULL to kfree. Paolo > Add the check and free to avoid unknown errors. > > Signed-off-by: Haiwei Li > --- >  virt/kvm/kvm_main.c | 5 ++++- >  1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 67ae2d5..18a32e1 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -617,8 +617,11 @@ static void kvm_destroy_vm_debugfs(struct kvm *kvm) >      debugfs_remove_recursive(kvm->debugfs_dentry); > >      if (kvm->debugfs_stat_data) { > -        for (i = 0; i < kvm_debugfs_num_entries; i++) > +        for (i = 0; i < kvm_debugfs_num_entries; i++) { > +            if (!kvm->debugfs_stat_data[i]) > +                break; >              kfree(kvm->debugfs_stat_data[i]); > +        } >          kfree(kvm->debugfs_stat_data); >      } >  } > -- > 1.8.3.1 >