** Description changed: + [Impact] + + * A deadlock in the connect/disconnect code is present in qemu 6.2 + + * backport the fix which moves the unlock a bit to avoid racing with + a lock triggered by clipboard unregistration. For more see the + referenced upstream commit + + [Test Plan] + + * start a qemu wit hvnc + qemu-system-x86_64 -vnc 127.0.0.1:0 ... + + * Connect and disconnect with VNC against it (TigerVNC is known + to work for this repro). You might wait a while in between + + * Without the fix at some point a race will occur which deadlocks qemu - + no interaction is possible anymore. + + [Where problems could occur] + + * Lock changes are always scary, but this one isn't too complex. + It is not rewriting all of it, just moving it up a few lines so + that qemu_clipboard_peer_unregister no mor is in its scope. + I can think of a problem if we'd find out later that inside of + that call we would have needed the lock to be held already. + It seems that isn't the case (it grabs the lock where needed), + but that is the issue I could think of. If that would happen it + would more likely then not be a deadlock but instead accessing + unsafe data which could lead to a variety of symptoms that are + hard to predict. + + [Other Info] + + * n/a + + --- original bug --- + There is a known bug that will cause VM deadlock, the patch should be merged and released: https://gitlab.com/qemu- project/qemu/-/commit/1dbbe6f172810026c51dc84ed927a3cc23017949#841723aa93098d8ab3b5068795e10ae7cf2a3179
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1970563 Title: Qemu 1:6.2+dfsg-2ubuntu6 deadlock bug To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1970563/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
