Most recent kernel where this bug did not occur: None Distribution: FC8 Hardware Environment: All Software Environment: All Problem Description: When echo some invalid values to /proc/acpi/processor/*/throttling, there isn't any error info returned, on the contray, it sets throttling value to some T* successfully, obviously, this is incorrect, a correct way should be to let it fail and return error info. Steps to reproduce: [root@localhost /]# echo "2xxxx" > /proc/acpi/processor/CPU0/throttling [root@localhost /]# cat /proc/acpi/processor/CPU0/throttling state count: 8 active state: T2 state available: T0 to T7 states: T0: 100% T1: 87% *T2: 75% T3: 62% T4: 50% T5: 37% T6: 25% T7: 12% [root@localhost /]# echo "" > /proc/acpi/processor/CPU0/throttling [root@localhost /]# cat /proc/acpi/processor/CPU0/throttling state count: 8 active state: T0 state available: T0 to T7 states: *T0: 100% T1: 87% T2: 75% T3: 62% T4: 50% T5: 37% T6: 25% T7: 12% [root@localhost /]# echo "7xxx" > /proc/acpi/processor/CPU0/throttling [root@localhost /]# cat /proc/acpi/processor/CPU0/throttling state count: 8 active state: T7 state available: T0 to T7 states: T0: 100% T1: 87% T2: 75% T3: 62% T4: 50% T5: 37% T6: 25% *T7: 12% [root@localhost /]#
Created attachment 14319 [details] This patch fixed this bug. This patch fixed the aforementioned issue, it also enables /proc/acpi/processor/*/throttling to accept such values as 't0' and 'T0', it also strictly limits /proc/acpi/processor/*/throttling only to accept "*", "t*" and "T*", "*" is the throttling state value the processor can support, current, it is 0 - 7.
patch in comment #1 applied to acpi-test
in Linus' tree as commit 3d532d5e3882c1387a2722df2a368c4a9224b12f