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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: Wed, 27 Nov 2019 19:32:32 +0100	[thread overview]
Message-ID: <6beeff56-7676-5dfd-a578-1732730f8963@redhat.com> (raw)
In-Reply-To: <bfa563e6a584bd85d3abe953ca088281dc0e167b.camel@linux.ibm.com>


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On 27/11/19 19:24, Leonardo Bras wrote:
> By what I could undestand up to now, these functions that use borrowed
> references can only be called while the reference (file descriptor)
> exists. 
> So, suppose these threads, where:
> - T1 uses a borrowed reference, and 
> - T2 is releasing the reference (close, release):

Nit: T2 is releasing the *last* reference (as implied by your reference
to close/release).

> 
> T1				| T2
> kvm_get_kvm()			|
> ...				| kvm_put_kvm()
> kvm_put_kvm_no_destroy()	|
> 
> The above would not trigger a use-after-free bug, but will cause a
> memory leak. Is my above understanding right?

Yes, this is correct.

Paolo


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  reply	other threads:[~2019-11-27 18:32 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 [this message]
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
2019-11-28 16:04                       ` Leonardo Bras
2019-11-26 17:57     ` Leonardo Bras

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