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From: Paolo Bonzini <pbonzini@redhat.com>
To: Salvatore Bonaccorso <carnil@debian.org>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	stable@vger.kernel.org, Wanpeng Li <kernellwp@gmail.com>
Subject: Re: [PATCH 1/2] KVM: SVM: avoid infinite loop on NPF from bad address
Date: Tue, 8 Jun 2021 09:17:34 +0200	[thread overview]
Message-ID: <24b6a7e2-5059-1c5c-aed1-1ea713d78bf3@redhat.com> (raw)
In-Reply-To: <YL70kh5/vLW8gmAY@eldamar.lan>

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


  reply	other threads:[~2021-06-08  7:17 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-17 16:38 [PATCH 0/2] KVM: fix set_memory_region_test on AMD Paolo Bonzini
2020-04-17 16:38 ` [PATCH 1/2] KVM: SVM: avoid infinite loop on NPF from bad address Paolo Bonzini
2020-04-21 19:56   ` Sasha Levin
2020-07-08  8:17   ` Wanpeng Li
2020-07-08  8:38     ` Paolo Bonzini
2020-07-08  9:08       ` Wanpeng Li
2020-07-08 11:10         ` Paolo Bonzini
2021-06-08  4:39   ` Salvatore Bonaccorso
2021-06-08  7:17     ` Paolo Bonzini [this message]
2022-01-13 16:27   ` Query about calling kvm_vcpu_gfn_to_memslot() with a GVA (Re: " Liam Merwick
2022-01-13 16:57     ` Sean Christopherson
2022-01-17 17:09       ` Liam Merwick
2022-01-18 18:46         ` Sean Christopherson
2020-04-17 16:38 ` [PATCH 2/2] selftests: kvm/set_memory_region_test: do not check RIP if the guest shuts down Paolo Bonzini

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