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perf: Enforce 1 as lower limit for perf_event_max_sample_rate

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/proc/sys/kernel/perf_event_max_sample_rate will accept
negative values as well as 0.

Negative values are unreasonable, and 0 causes a
divide by zero exception in perf_proc_update_handler.

This patch enforces a lower limit of 1.

Signed-off-by: Knut Petersen <Knut_Petersen@t-online.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5242DB0C.4070005@t-online.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Knut Petersen 2013-09-25 14:29:37 +02:00 committed by Ingo Molnar
parent 354cc40e3b
commit 723478c8a4
2 changed files with 2 additions and 1 deletions
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2
kernel/events/core.c
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@ -193,7 +193,7 @@ int perf_proc_update_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int ret = proc_dointvec(table, write, buffer, lenp, ppos);
int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (ret || !write)
return ret;

1
kernel/sysctl.c
View file

@ -1049,6 +1049,7 @@ static struct ctl_table kern_table[] = {
.maxlen = sizeof(sysctl_perf_event_sample_rate),
.mode = 0644,
.proc_handler = perf_proc_update_handler,
.extra1 = &one,
},
{
.procname = "perf_cpu_time_max_percent",