1) No, it is not appropriate to test a non LTS kernel on a LTS distribution.
2) I did you a favor and tested on the previous LTS kernel (linux- image-5.4.0-28-generic) and the latest LTS kernel (linux- image-5.4.0-31-generic) and could not reproduce on either after running dd 3-5 times on each. However, the kernel I reported on (linux-image-5.4.0-29-generic) produced the stack trace after the 2nd attempt. Maybe I didn't collect enough samples, but the point here is the previous kernel was not broken, nor is the latest. Something may be different in linux- image-5.4.0-29-generic. May 22 20:12:39 quad kernel: [ 1088.902612] INFO: task systemd-udevd:451 blocked for more than 120 seconds. May 22 20:12:39 quad kernel: [ 1088.902618] Tainted: P IOE 5.4.0-29-generic #33-Ubuntu May 22 20:12:39 quad kernel: [ 1088.902620] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. May 22 20:12:39 quad kernel: [ 1088.902623] systemd-udevd D 0 451 1 0x00004124 May 22 20:12:39 quad kernel: [ 1088.902626] Call Trace: May 22 20:12:39 quad kernel: [ 1088.902636] __schedule+0x2e3/0x740 May 22 20:12:39 quad kernel: [ 1088.902639] schedule+0x42/0xb0 May 22 20:12:39 quad kernel: [ 1088.902641] schedule_preempt_disabled+0xe/0x10 May 22 20:12:39 quad kernel: [ 1088.902644] __mutex_lock.isra.0+0x182/0x4f0 May 22 20:12:39 quad kernel: [ 1088.902649] ? exact_lock+0x11/0x20 May 22 20:12:39 quad kernel: [ 1088.902652] __mutex_lock_slowpath+0x13/0x20 May 22 20:12:39 quad kernel: [ 1088.902654] mutex_lock+0x2e/0x40 May 22 20:12:39 quad kernel: [ 1088.902658] __blkdev_get+0x78/0x550 May 22 20:12:39 quad kernel: [ 1088.902661] blkdev_get+0x3d/0x140 May 22 20:12:39 quad kernel: [ 1088.902663] ? blkdev_get_by_dev+0x50/0x50 May 22 20:12:39 quad kernel: [ 1088.902665] blkdev_open+0x8f/0xa0 May 22 20:12:39 quad kernel: [ 1088.902670] do_dentry_open+0x143/0x3a0 May 22 20:12:39 quad kernel: [ 1088.902672] vfs_open+0x2d/0x30 May 22 20:12:39 quad kernel: [ 1088.902676] do_last+0x194/0x900 May 22 20:12:39 quad kernel: [ 1088.902679] path_openat+0x8d/0x290 May 22 20:12:39 quad kernel: [ 1088.902682] do_filp_open+0x91/0x100 May 22 20:12:39 quad kernel: [ 1088.902686] ? __alloc_fd+0x46/0x150 May 22 20:12:39 quad kernel: [ 1088.902689] do_sys_open+0x17e/0x290 May 22 20:12:39 quad kernel: [ 1088.902691] __x64_sys_openat+0x20/0x30 May 22 20:12:39 quad kernel: [ 1088.902695] do_syscall_64+0x57/0x190 May 22 20:12:39 quad kernel: [ 1088.902699] entry_SYSCALL_64_after_hwframe+0x44/0xa9 May 22 20:12:39 quad kernel: [ 1088.902702] RIP: 0033:0x7f31ed7bdd1b May 22 20:12:39 quad kernel: [ 1088.902709] Code: Bad RIP value. May 22 20:12:39 quad kernel: [ 1088.902710] RSP: 002b:00007ffdc7cf3f50 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 May 22 20:12:39 quad kernel: [ 1088.902712] RAX: ffffffffffffffda RBX: 00007ffdc7cf4060 RCX: 00007f31ed7bdd1b May 22 20:12:39 quad kernel: [ 1088.902714] RDX: 00000000000a0800 RSI: 000055f3f78a27d0 RDI: 00000000ffffff9c May 22 20:12:39 quad kernel: [ 1088.902715] RBP: 000055f3f78a27d0 R08: 000055f3f66940c0 R09: 0000000000000000 May 22 20:12:39 quad kernel: [ 1088.902716] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000a0800 May 22 20:12:39 quad kernel: [ 1088.902717] R13: 000055f3f78759d0 R14: 00007ffdc7cf4028 R15: ffffffff00000001 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1879017 Title: dd caused systemd-udevd call trace To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1879017/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
