Hmm, are you sure that your phone rebooted in idle after 3 days of stable work because of the kernel? What was the reboot reason? Will you describe what exactly has happened.
And BTW next time you lock 250 as frequency to test what value SR calculates, do it without charger attached. As now you have :
250 - vdd1_opp: 2 sr_vdd1_voltage: 23 500 - vdd1_opp: 3 sr_vdd1_voltage: 35 550 - vdd1_opp: 4 sr_vdd1_voltage: 54 600 - vdd1_opp: 4 sr_vdd1_voltage: 41 720 - vdd1_opp: 6 sr_vdd1_voltage: 60 805 - vdd1_opp: 7 sr_vdd1_voltage: 60 850 - vdd1_opp: 8 sr_vdd1_voltage: 52 900 - vdd1_opp: 9 sr_vdd1_voltage: 60