printk deadlock in 9.4.z kernels
Issue
After upgrading to 4.16.21 bare metal nodes experienced hard lockup panics when printing to the serial console. The system crashed due to a deadlock between dump_stack_lvl() and serial8250_console_write()
NMI watchdog: Watchdog detected hard LOCKUP on cpu
Environment
- Red Hat Enterprise Linux 9.3
- Red Hat Enterprise Linux 9.4
- OpenShift versions:
- 4.16.21, 4.16.22, 4.16.23 and 4.16.24
- 4.17.4, 4.17.5 and 4.17.6
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