It has been a long time since last release. In this new release, we rebased our codes to upstream LTS 4.19.57, with extra updates as follows:

Notable Changes

• In this release, we set cubic as default TCP congestion control algorithm instead of bbr, due to a performance degradation observed in production system. The troubleshooting process and solution could be found at this Kbase article.
• CVE-2019-1125: the latest Spectre SWAPGS gadget vulnerability fix;

Bug Fixes

• mm/page-writeback.c: fix range_cyclic writeback vs writepages deadlock (Dave Chinner)
• block: fix single range discard merge (Ming Lei)
• NFSv4.x: fix lock recovery during delegation recall (Olga Kornievskaia)
• block: fix the DISCARD request merge (Jianchao Wang)
• dm raid: fix false -EBUSY when handling check/repair message (Heinz Mauelshagen)
• xfs: fix use-after-free race in xfs_buf_rele (Dave Chinner)
• x86: uaccess: Inhibit speculation past access_ok() in user_access_begin() (Will Deacon)
• make 'user_access_begin()' do 'access_ok()' (Linus Torvalds)
• i915: fix missing user_access_end() in page fault exception case (Linus Torvalds)
• drm/i915: Force the slow path after a user-write error (Chris Wilson)
• userfaultfd: allow get_mempolicy(MPOL_F_NODE|MPOL_F_ADDR) to trigger userfaults (Andrea Arcangeli)
• random: speed up the initialization of module (Xingjun Liu)
• random: introduce the initialization seed (Xingjun Liu)
• cpufreq/intel_pstate: Load only on Intel hardware (Shanpei Chen)
• cpufreq: intel_pstate: Add reasons for failure and debug messages (Shanpei Chen)
• cpufreq: intel_pstate: Force HWP min perf before offline (Shanpei Chen)
• ptrace: Fix ->ptracer_cred handling for PTRACE_TRACEME (Jann Horn)
• dm: add missing trace_block_split() to __split_and_process_bio() (Mike Snitzer)
• dm: fix dm_wq_work() to only use __split_and_process_bio() if appropriate (Mike Snitzer)
• dm: avoid indirect call in __dm_make_request (Mikulas Patocka)
• dm: fix redundant IO accounting for bios that need splitting (Mike Snitzer)
• dm: fix clone_bio() to trigger blk_recount_segments() (Mike Snitzer)
• NFS: Fix dentry revalidation on NFSv4 lookup (Trond Myklebust)
• ext4: unlock unused_pages timely when doing writeback (Xiaoguang Wang)
• x86/kvmclock: set offset for kvm unstable clock (Pavel Tatashin)
• xfs: serialize unaligned dio writes against all other dio writes (Brian Foster)