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Fri, 03 Feb 2023 13:35:53 -0800 (PST) X-Google-Smtp-Source: AK7set8GiBZNAUhnppz+3LpmWjBO/5Dhk61WY57QRLNeBIn7RbRA8vBDcQoGmES9jBCpRxioDalZzw== X-Received: by 2002:a05:6e02:148c:b0:312:7bbf:94f5 with SMTP id n12-20020a056e02148c00b003127bbf94f5mr9262252ilk.3.1675460153111; Fri, 03 Feb 2023 13:35:53 -0800 (PST) Received: from redhat.com ([38.15.36.239]) by smtp.gmail.com with ESMTPSA id a16-20020a924450000000b0031264571bd8sm1103072ilm.18.2023.02.03.13.35.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Feb 2023 13:35:52 -0800 (PST) Date: Fri, 3 Feb 2023 14:35:51 -0700 From: Alex Williamson To: Matthew Rosato Cc: "Liu, Yi L" , "Tian, Kevin" , "pbonzini@redhat.com" , "jgg@nvidia.com" , "cohuck@redhat.com" , "farman@linux.ibm.com" , "pmorel@linux.ibm.com" , "borntraeger@linux.ibm.com" , "frankja@linux.ibm.com" , "imbrenda@linux.ibm.com" , "david@redhat.com" , "akrowiak@linux.ibm.com" , "jjherne@linux.ibm.com" , "pasic@linux.ibm.com" , "zhenyuw@linux.intel.com" , "Wang, Zhi A" , "Christopherson, , Sean" , "linux-s390@vger.kernel.org" , "kvm@vger.kernel.org" , "intel-gvt-dev@lists.freedesktop.org" , "intel-gfx@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v3] vfio: fix deadlock between group lock and kvm lock Message-ID: <20230203143551.2f349702.alex.williamson@redhat.com> In-Reply-To: References: <20230202162442.78216-1-mjrosato@linux.ibm.com> <20230202124210.476adaf8.alex.williamson@redhat.com> <20230202161307.0c6aa23e.alex.williamson@redhat.com> <20230203064940.435e4d65.alex.williamson@redhat.com> <20230203081942.64fbf9f1.alex.williamson@redhat.com> <20230203133503.4d8fb3e8.alex.williamson@redhat.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.35; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 3 Feb 2023 16:19:10 -0500 Matthew Rosato wrote: > > @@ -350,32 +350,25 @@ void vfio_device_get_kvm_safe(struct vfio_device *device) > > > > lockdep_assert_held(&device->dev_set->lock); > > > > - spin_lock(&device->group->kvm_ref_lock); > > - if (!device->group->kvm) > > - goto unlock; > > - > > pfn = symbol_get(kvm_put_kvm); > > if (WARN_ON(!pfn)) > > - goto unlock; > > + return; > > > > fn = symbol_get(kvm_get_kvm_safe); > > if (WARN_ON(!fn)) { > > symbol_put(kvm_put_kvm); > > - goto unlock; > > + return; > > } > > > ret = fn(device->group->kvm); > > s/device->group->kvm/kvm/ Oops, yes. > With that small change, this looks good to me too (and testing looks > good too). Do you want me to send a v4 for one last round of review? Please do. Thanks, Alex