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([2001:b07:6468:f312:5e2c:eb9a:a8b6:fd3e]) by smtp.gmail.com with ESMTPSA id h9sm1885572wmm.33.2021.06.08.00.17.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Jun 2021 00:17:35 -0700 (PDT) To: Salvatore Bonaccorso Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Sean Christopherson , stable@vger.kernel.org, Wanpeng Li References: <20200417163843.71624-1-pbonzini@redhat.com> <20200417163843.71624-2-pbonzini@redhat.com> From: Paolo Bonzini Subject: Re: [PATCH 1/2] KVM: SVM: avoid infinite loop on NPF from bad address Message-ID: <24b6a7e2-5059-1c5c-aed1-1ea713d78bf3@redhat.com> Date: Tue, 8 Jun 2021 09:17:34 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 08/06/21 06:39, Salvatore Bonaccorso wrote: > > Did this simply felt through the cracks here or is it not worth > backporting to older series? At least > https://bugzilla.redhat.com/show_bug.cgi?id=1947982#c3 seem to > indicate it might not be worth of if there is risk for regression if I > understand Wanpeng Li. Is this right? It's not particularly interesting, because the loop can be broken with just Ctrl-C (or any signal for that matter) and the guest was misbehaving anyway. You can read from that bugzilla link my opinion on this "vulnerability": if you run a VM for somebody and they want to waste your CPU time, they can just run a while(1) loop. It's a bug and it is caught by the kvm-unit-tests, so I marked it for stable at the time because it can be useful to run kvm-unit-tests on stable kernels and hanging is a bit impolite (the test harness has a timeout, but of course tests that hang have the risk missing other regressions). I will review gladly a backport, but if it is just because of that CVE report, documenting that the vulnerability is bogus would be time spent better that doing and testing the backport. Paolo