perf: Enforce 1 as lower limit for perf_event_max_sample_rate (723478c8) · Commits · 戴 / test

/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>

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",

Admin message