When code is upgraded to 21.4R3-S2.4 on a EX or QFX platform, everything came up fine but after some time it starts having an endless stream of these messages:

dc-pfe: Frame 9: sp = 0x25e51bd0, pc = 0x83acbb2 Message from syslogd

dc-pfe: SCHED: Thread 11 (Ethernet) ran for 1007 ms without yielding Message from syslogd

dc-pfe: Scheduler Oinker

System Zeroize also doesn't help

When the box lands into this state it is impossible to see any output since it scrolls by so fast, and only a reboot allows you 5 minutes or so before it spams the messages again.

The only way to recover is to do Junos Recovery of the box and roll it back to the previous stable image and then upgrade the box with 21.4R3-S5 or higher release.