Marking verification done, though I've not had explicit testing results from Amazon. Their comment in SF:#00308561 was, "thanks for putting in the extra effort to get this released so quickly." By that I assume they have been successfully using the test kernel as this bug was an arm64 show stopper for them.
** Tags removed: verification-needed-bionic verification-needed-focal verification-needed-groovy verification-needed-hirsute ** Tags added: verification-done-bionic verification-done-focal verification-done-groovy verification-done-hirsute -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux-aws in Ubuntu. https://bugs.launchpad.net/bugs/1926184 Title: locking/qrwlock: Fix ordering in queued_write_lock_slowpath() Status in linux package in Ubuntu: In Progress Status in linux-aws package in Ubuntu: In Progress Status in linux source package in Bionic: Fix Committed Status in linux-aws source package in Bionic: Fix Released Status in linux source package in Focal: Fix Committed Status in linux-aws source package in Focal: Fix Released Status in linux source package in Groovy: Fix Committed Status in linux-aws source package in Groovy: Confirmed Status in linux source package in Hirsute: Fix Committed Status in linux-aws source package in Hirsute: Confirmed Bug description: [Impact] * Out of order reads can fetch a NULL pointer causing a kernel crash. Affects kernels from v4.15 to v5.11. [Fix] * commit 84a24bf8c52e ("locking/qrwlock: Fix ordering in queued_write_lock_slowpath()") * For Bionic, we also require an additional patch: commit fcfdfe30e324 ("locking/barriers: Introduce smp_cond_load_relaxed() and atomic_cond_read_relaxed()") [Where problems could occur] * This is quite a subtle bug. It is more prevalent on arm64. Regression possibility seems quite low. The worst impact could be a minor performance degradation. * Kernels 4.15 / 5.4 / 5.8 / 5.11 were successfully built and booted with this patch. Also, by using ftrace we could see that the changed function was executed with success multiple times. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1926184/+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
