From: Paolo Bonzini <pbonzini@redhat.com>
To: Leonardo Bras <leonardo@linux.ibm.com>,
Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Paul Mackerras" <paulus@ozlabs.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
kvm-ppc@vger.kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] KVM: Add separate helper for putting borrowed reference to kvm
Date: Thu, 28 Nov 2019 14:49:42 +0100 [thread overview]
Message-ID: <a924cb9c-8354-23fe-1052-8ad564edad7f@redhat.com> (raw)
In-Reply-To: <41fe3962ce1f1d5f61db5f5c28584f68ad66b2b1.camel@linux.ibm.com>
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On 27/11/19 22:57, Leonardo Bras wrote:
> But on the above case, kvm_put_kvm{,_no_destroy}() would be called
> with refcount == 1, and if reorder patch is applied, it would not cause
> any use-after-free error, even on kvm_put_kvm() case.
I think this is what you're missing: kvm_put_kvm_no_destroy() does not
protect against bugs in the code that uses it. It protect against bugs
_elsewhere_.
Therefore, kvm_put_kvm_no_destroy() is always a better choice when
applicable, because it turns bugs in _other parts of the code_ from
use-after-free to WARN+leak.
Paolo
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next prev parent reply other threads:[~2019-11-28 13:50 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-21 22:58 [PATCH] KVM: Add separate helper for putting borrowed reference to kvm Sean Christopherson
2019-10-22 13:49 ` Paolo Bonzini
2019-11-26 16:44 ` Leonardo Bras
2019-11-26 17:14 ` Sean Christopherson
2019-11-26 17:53 ` Leonardo Bras
2019-11-27 16:38 ` Paolo Bonzini
2019-11-27 18:24 ` Leonardo Bras
2019-11-27 18:32 ` Paolo Bonzini
2019-11-27 19:25 ` Leonardo Bras
2019-11-27 19:47 ` Sean Christopherson
2019-11-27 20:15 ` Leonardo Bras
2019-11-27 21:57 ` Leonardo Bras
2019-11-28 1:00 ` Sean Christopherson
2019-11-28 16:29 ` Leonardo Bras
2019-11-28 13:49 ` Paolo Bonzini [this message]
2019-11-28 16:04 ` Leonardo Bras
2019-11-26 17:57 ` Leonardo Bras
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