I built xenial and bionic test kernels, both with commit ce28867fd20c. The test kernels can be downloaded from: http://kernel.ubuntu.com/~jsalisbury/lp1786057
Can you test these kernels and see if they resolve this bug? Note about installing test kernels: * If the test kernel is prior to 4.15(Bionic) you need to install the linux-image and linux-image-extra .deb packages. * If the test kernel is 4.15(Bionic) or newer, you need to install the linux-modules, linux-modules-extra and linux-image-unsigned .deb packages. Thanks in advance! -- 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/1786057 Title: qeth: don't clobber buffer on async TX completion 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 Status in linux source package in Bionic: In Progress Bug description: Description: qeth: don't clobber buffer on async TX completion Symptom: Failing transmissions on af_iucv HiperTransport socket. Problem: If qeth_qdio_output_handler() detects that a transmit requires async completion, it replaces the pending buffer's metadata object (qeth_qdio_out_buffer) so that this queue buffer can be re-used while the data is pending completion. Later when the CQ indicates async completion of such a metadata object, qeth_qdio_cq_handler() tries to free any data associated with this object (since HW has now completed the transfer). By calling qeth_clear_output_buffer(), it erronously operates on the queue buffer that _previously_ belonged to this transfer ... but which has been potentially re-used several times by now. This results in double-free's of the buffer's data, and failing transmits as the buffer descriptor is scrubbed in mid-air. Solution: First only scrub the queue buffer when it is prepared for re-use, and later obtain the data addresses from the async-completion notifier (ie. the AOB), instead of the queue buffer. Reproduction: Heavy multi-connection workload on an af_iucv HiperTransport socket. Upstream-ID: ce28867fd20c23cd769e78b4d619c4755bf71a1c Kernel 4.18 Will be introduced with kernel 4.18 in Cosmic. But should also be applied to Bionic and Xenial To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1786057/+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
