Submitted Xenial SRU request: https://lists.ubuntu.com/archives/kernel-team/2018-March/090640.html
** Description changed: + == SRU Justification == + Description: qeth: fix calculation of required buffer elements for skb Symptom: Repeated device recovery due to Subchannel Program Checks Problem: skbs of certain lengths cause qeth to miscalculate the - number of needed IO buffer elements, resulting in - malformed TX buffer descriptors. When such a buffer is - presented to the HW, it triggers a Subchannel Program - Check. qeth handles this by starting device recovery. + number of needed IO buffer elements, resulting in + malformed TX buffer descriptors. When such a buffer is + presented to the HW, it triggers a Subchannel Program + Check. qeth handles this by starting device recovery. Solution: Fix the buffer element calculation, so that qeth builds - proper TX buffer descriptors. + proper TX buffer descriptors. Reproduction: Occurs for skbs where the last byte of the linear data - range / of a page frag sits on a page boundary. + range / of a page frag sits on a page boundary. Upstream Git Commit: 89271c65edd599207dd982007900506283c90ae3 kernel 4.16 - backported to xenial/master-next Here's a backport of the upstream commit for pre-4.8 kernels. -- 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/1750810 Title: qeth: fix calculation of required buffer elements for skb Status in Ubuntu on IBM z Systems: In Progress Status in linux package in Ubuntu: In Progress Status in linux source package in Xenial: In Progress Bug description: == SRU Justification == Description: qeth: fix calculation of required buffer elements for skb Symptom: Repeated device recovery due to Subchannel Program Checks Problem: skbs of certain lengths cause qeth to miscalculate the number of needed IO buffer elements, resulting in malformed TX buffer descriptors. When such a buffer is presented to the HW, it triggers a Subchannel Program Check. qeth handles this by starting device recovery. Solution: Fix the buffer element calculation, so that qeth builds proper TX buffer descriptors. Reproduction: Occurs for skbs where the last byte of the linear data range / of a page frag sits on a page boundary. Upstream Git Commit: 89271c65edd599207dd982007900506283c90ae3 kernel 4.16 backported to xenial/master-next Here's a backport of the upstream commit for pre-4.8 kernels. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1750810/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
