Hello, I previously reported a hang when building LLVM+clang on a block multi-queue device (NVMe _or_ loopback onto tmpfs with the ’none’ scheduler). I’ve since updated the kernel to 4.15-rc9, merged the ‘blkmq/for-next’ branch, disabled nohz_full parameter (used for testing), and tried again. Both NVMe and loopback now lock up hard (ext4 if it matters). Here are the backtraces: NVMe: http://znu.io/IMG_0366.jpg Loopback: http://znu.io/IMG_0367.jpg What should I try next to help debug this? Dave
