From: Yi Yang <yi.y.yang@xxxxxxxxx> http://bugzilla.kernel.org/show_bug.cgi?id=9704 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. 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. Before applying this patch, the test result is below: [root@localhost acpi]# cat /proc/acpi/processor/CPU0/throttling state count: 8 active state: T1 state available: T0 to T7 states: T0: 100% *T1: 87% T2: 75% T3: 62% T4: 50% T5: 37% T6: 25% T7: 12% [root@localhost acpi]# echo "1xxxxxx" > /proc/acpi/processor/CPU0/throttling [root@localhost acpi]# cat /proc/acpi/processor/CPU0/throttling state count: 8 active state: T1 state available: T0 to T7 states: T0: 100% *T1: 87% T2: 75% T3: 62% T4: 50% T5: 37% T6: 25% T7: 12% [root@localhost acpi]# echo "0" > /proc/acpi/processor/CPU0/throttling [root@localhost acpi]# 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 acpi]# cd / [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 "T0" > /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 "T7" > /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 "T100" > /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 "xxx" > /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 "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 "7777" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [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 /]# After applying this patch, the test result is below: [root@localhost linux-2.6.24-rc6]# echo > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "0" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo "t0" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo "T0" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# 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 linux-2.6.24-rc6]# echo "T7" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# 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 linux-2.6.24-rc6]# echo "T8" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# vi drivers/acpi/processor_throttling.c [root@localhost linux-2.6.24-rc6]# echo "T8" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "t7" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo "t70" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "70" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "7000" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "70" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo "xxx" > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo -n > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo -n "" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo $? 0 [root@localhost linux-2.6.24-rc6]# echo -n "" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# 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 linux-2.6.24-rc6]# echo -n "" > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# 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 linux-2.6.24-rc6]# echo t0 > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo T0 > /proc/acpi/processor/CPU0/throttling [root@localhost linux-2.6.24-rc6]# echo Tt0 > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# echo T > /proc/acpi/processor/CPU0/throttling -bash: echo: write error: Invalid argument [root@localhost linux-2.6.24-rc6]# Signed-off-by: Yi Yang <yi.y.yang@xxxxxxxxx> Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- drivers/acpi/processor_throttling.c | 24 ++++++++++++++++++++---- 1 files changed, 20 insertions(+), 4 deletions(-) diff --git a/drivers/acpi/processor_throttling.c b/drivers/acpi/processor_throttling.c index bb06738..4d4d8d8 100644 --- a/drivers/acpi/processor_throttling.c +++ b/drivers/acpi/processor_throttling.c @@ -1232,7 +1232,10 @@ static ssize_t acpi_processor_write_throttling(struct file *file, int result = 0; struct seq_file *m = file->private_data; struct acpi_processor *pr = m->private; - char state_string[12] = { '\0' }; + char state_string[5] = ""; + char *charp = NULL; + size_t state_val = 0; + char tmpbuf[5] = ""; if (!pr || (count > sizeof(state_string) - 1)) return -EINVAL; @@ -1241,10 +1244,23 @@ static ssize_t acpi_processor_write_throttling(struct file *file, return -EFAULT; state_string[count] = '\0'; + if ((count > 0) && (state_string[count-1] == '\n')) + state_string[count-1] = '\0'; - result = acpi_processor_set_throttling(pr, - simple_strtoul(state_string, - NULL, 0)); + charp = state_string; + if ((state_string[0] == 't') || (state_string[0] == 'T')) + charp++; + + state_val = simple_strtoul(charp, NULL, 0); + if (state_val >= pr->throttling.state_count) + return -EINVAL; + + snprintf(tmpbuf, 5, "%d", state_val); + + if (strcmp(tmpbuf, charp) != 0) + return -EINVAL; + + result = acpi_processor_set_throttling(pr, state_val); if (result) return result; -- 1.5.6 -- To 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