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Tsirkin" To: Sean Christopherson Cc: Sebastian Andrzej Siewior , Paolo Bonzini , Jason Wang , kvm@vger.kernel.org, virtualization@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/3] vhost_task: Fix a bug where KVM wakes an exited task Message-ID: <20250918133938-mutt-send-email-mst@kernel.org> References: <20250827194107.4142164-1-seanjc@google.com> <20250827201059.EmmdDFB_@linutronix.de> <20250918110828-mutt-send-email-mst@kernel.org> <20250918154826.oUc0cW0Y@linutronix.de> <20250918120658-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Sep 18, 2025 at 09:52:19AM -0700, Sean Christopherson wrote: > On Thu, Sep 18, 2025, Michael S. Tsirkin wrote: > > On Thu, Sep 18, 2025 at 09:04:07AM -0700, Sean Christopherson wrote: > > > On Thu, Sep 18, 2025, Sebastian Andrzej Siewior wrote: > > > > On 2025-09-18 11:09:05 [-0400], Michael S. Tsirkin wrote: > > > > > So how about switching to this approach then? > > > > > Instead of piling up fixes like we seem to do now ... > > > > > > I don't have a strong preference for 6.17, beyond landing a fix of some kind. > > > I think there are three options for 6.17, in order of "least like to break > > > something": > > > > > > 1. Sebastian's get_task_struct() fix > > > > > > I am just a bit apprehensive that we don't create a situation > > where we leak the task struct somehow, given the limited > > testing time. Can you help me get convinced that risk is 0? > > I doubt it, I share same similar concerns about lack of testing. So I guess > thinking about this again, #2 is probably safer since it'd only impact KVM? I can't say I understand completely how we get that state though? Why did the warning trigger if it's not a UAF? > > > 2. This series, without the KILLED sanity check in __vhost_task_wake() > > > 3. This series, with my fixup (with which syzbot was happy)