printk timing issues on boot

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Environment

SUSE Linux Enterprise Server 12SP4 for SAP

Situation

During bootup printk stack trace messages generated on console.Server times out for a period of time.

Resolution

pleas execute the following command

echo '3 4 1 7' > /proc/sys/kernel/printk

To make the change persistent, we would need to do
[1] Edit "/etc/sysctl.conf" and set "kernel.printk" to
kernel.printk = 3 4 1 7
2] Then run "sysctl -p" to make the change effective

Cause

Default settings for printk on SLES12 SP4 is:

# /proc/sys/kernel/printk
7    4    1    7

Status

Reported to Engineering

Additional Information

Customer saw on issue on RHEL image that had caused similar timing issues: The printk issue mentioned is related to https://bugzilla.kernel.org/show_bug.cgi?id=199003 The patch for this has been there for some time https://lkml.org/lkml/2016/4/22/487

Disclaimer

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