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Commit 723478c8 authored by Knut Petersen's avatar Knut Petersen Committed by Ingo Molnar
Browse files

perf: Enforce 1 as lower limit for perf_event_max_sample_rate 



/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: default avatarKnut Petersen <Knut_Petersen@t-online.de>
Signed-off-by: default avatarPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5242DB0C.4070005@t-online.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 354cc40e

kernel/events/core.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

kernel/sysctl.c

+1 −0
Original line number Diff line number Diff line
@@ -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",