Public bug reported: The HWE kernel, and possibly others too, backport some virtio improvements related to setting VIRTIO_NET_HDR_F_DATA_VALID on received packets so that the CPU doesn't have to checksum packets that have already been verified by hardware. In the initial implementation of this, the kernel erroneously set this flag too for transmitted packets, which is explicitly forbidden by the virtio spec. It was rectified in these two commits:
501db511397fd6efff3aa5b4e8de415b55559550 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=501db511397fd6efff3aa5b4e8de415b55559550 6391a4481ba0796805d6581e42f9f0418c099e34 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6391a4481ba0796805d6581e42f9f0418c099e34 Both of these must be backported into your HWE kernel and perhaps other Ubuntu kernels too. (They were both backported into the kernel.org stable kernels.) While mostly nobody cares about this "correctness" issue, it turns out that Google Cloud Platform -- which uses the HWE kernel by default -- does care and will silently and mysteriously drop packets. This leads to packets being dropped entirely when being forwarded between various types of network drivers. This issue must be fixed in order to use Ubuntu on Google Cloud Platform. ** Affects: linux (Ubuntu) Importance: Undecided Status: Incomplete ** Description changed: The HWE kernel, and possibly others too, backport some virtio improvements related to setting VIRTIO_NET_HDR_F_DATA_VALID on received packets so that the CPU doesn't have to checksum packets that have already been verified by hardware. In the initial implementation of - this, the kernel erroneously set this flag too for transmitted flags, + this, the kernel erroneously set this flag too for transmitted packets, which is explicitly forbidden by the virtio spec. It was rectified in these two commits: 501db511397fd6efff3aa5b4e8de415b55559550 6391a4481ba0796805d6581e42f9f0418c099e34 Both of these must be backported into your HWE kernel, and others too. While mostly nobody cares about this "correctness" issue, it turns out that Google Cloud Platform -- which uses the HWE kernel by default -- does care and will silently and mysteriously drop packets. This leads to packets being dropped entirely when being forwarded between various types of network drivers. This issue must be fixed in order to use Ubuntu on Google Cloud Platform. ** Description changed: The HWE kernel, and possibly others too, backport some virtio improvements related to setting VIRTIO_NET_HDR_F_DATA_VALID on received packets so that the CPU doesn't have to checksum packets that have already been verified by hardware. In the initial implementation of this, the kernel erroneously set this flag too for transmitted packets, which is explicitly forbidden by the virtio spec. It was rectified in these two commits: 501db511397fd6efff3aa5b4e8de415b55559550 6391a4481ba0796805d6581e42f9f0418c099e34 - Both of these must be backported into your HWE kernel, and others too. - While mostly nobody cares about this "correctness" issue, it turns out - that Google Cloud Platform -- which uses the HWE kernel by default -- - does care and will silently and mysteriously drop packets. This leads to - packets being dropped entirely when being forwarded between various - types of network drivers. + Both of these must be backported into your HWE kernel, and perhaps other + Ubuntu kernels too. While mostly nobody cares about this "correctness" + issue, it turns out that Google Cloud Platform -- which uses the HWE + kernel by default -- does care and will silently and mysteriously drop + packets. This leads to packets being dropped entirely when being + forwarded between various types of network drivers. This issue must be fixed in order to use Ubuntu on Google Cloud Platform. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1685416 Title: Virtio Fixes Not Backported --> Google Cloud Platform Drops Packets Status in linux package in Ubuntu: Incomplete Bug description: The HWE kernel, and possibly others too, backport some virtio improvements related to setting VIRTIO_NET_HDR_F_DATA_VALID on received packets so that the CPU doesn't have to checksum packets that have already been verified by hardware. In the initial implementation of this, the kernel erroneously set this flag too for transmitted packets, which is explicitly forbidden by the virtio spec. It was rectified in these two commits: 501db511397fd6efff3aa5b4e8de415b55559550 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=501db511397fd6efff3aa5b4e8de415b55559550 6391a4481ba0796805d6581e42f9f0418c099e34 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6391a4481ba0796805d6581e42f9f0418c099e34 Both of these must be backported into your HWE kernel and perhaps other Ubuntu kernels too. (They were both backported into the kernel.org stable kernels.) While mostly nobody cares about this "correctness" issue, it turns out that Google Cloud Platform -- which uses the HWE kernel by default -- does care and will silently and mysteriously drop packets. This leads to packets being dropped entirely when being forwarded between various types of network drivers. This issue must be fixed in order to use Ubuntu on Google Cloud Platform. 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