Comment 48 for bug 1942935

Noticed this issue on Ubuntu 20.04 with a md raid device. System exhibited the same behavior as other users have noted: high CPU usage and terminal locking up until the system is rebooted.

[14715252.569157] INFO: task md1_raid4:1763945 blocked for more than 120 seconds.
[14715252.570228] Not tainted 5.4.0-146-generic #163-Ubuntu
[14715252.571277] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[14715252.572347] md1_raid4 D 0 1763945 2 0x80004000
[14715252.572357] Call Trace:
[14715252.572360] __schedule+0x2e3/0x740
[14715252.572363] schedule+0x42/0xb0
[14715252.572369] raid5d+0x3e6/0x5f0 [raid456]
[14715252.572376] ? schedule_timeout+0x10e/0x160
[14715252.572381] ? __wake_up_pollfree+0x40/0x40
[14715252.572384] md_thread+0x97/0x160
[14715252.572392] ? __wake_up_pollfree+0x40/0x40
[14715252.572394] kthread+0x104/0x140
[14715252.572399] ? md_start_sync+0x60/0x60
[14715252.572403] ? kthread_park+0x90/0x90
[14715252.572405] ret_from_fork+0x35/0x40
[14715252.572430] INFO: task kworker/u64:1:3189415 blocked for more than 120 seconds.