Hi Greg, Sasha,
Can you cherry-pick these two sysrq patches to LTS kernels? They're introduced in v5.1-rc1 and should go to all prior LTS versions.
commit 075e1a0c50f59ea210561d0d0fedbd945615df78 Author: Petr Mladek pmladek@suse.com Date: Fri Jan 11 13:45:15 2019 +0100
sysrq: Restore original console_loglevel when sysrq disabled
The sysrq header line is printed with an increased loglevel to provide users some positive feedback.
The original loglevel is not restored when the sysrq operation is disabled. This bug was introduced in 2.6.12 (pre-git-history) by the commit ("Allow admin to enable only some of the Magic-Sysrq functions").
commit c3fee60908db4a8594f2e4a2131998384b8fa006 Author: Petr Mladek pmladek@suse.com Date: Fri Jan 11 17:20:37 2019 +0100
sysrq: Remove duplicated sysrq message
The commit 97f5f0cd8cd0a0544 ("Input: implement SysRq as a separate input handler") added pr_fmt() definition. It caused a duplicated message prefix in the sysrq header messages, for example:
[ 177.053931] sysrq: SysRq : Show backtrace of all active CPUs [ 742.864776] sysrq: SysRq : HELP : loglevel(0-9) reboot(b) crash(c)
Fixes: 97f5f0cd8cd0a05 ("Input: implement SysRq as a separate input handler")