From: Knut Petersen Date: Wed, 25 Sep 2013 12:29:37 +0000 (+0200) Subject: perf: Enforce 1 as lower limit for perf_event_max_sample_rate X-Git-Url: http://git.mmlx.us/?a=commitdiff_plain;h=02f98e3e36da106338b7c732fed516420fb20e2a;p=linux-edison.git perf: Enforce 1 as lower limit for perf_event_max_sample_rate commit 723478c8a471403c53cf144999701f6e0c4bbd11 upstream. /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 Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/5242DB0C.4070005@t-online.de Signed-off-by: Ingo Molnar Cc: Weng Meiling Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/events/core.c b/kernel/events/core.c index bffea4900db..459b94c9472 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -190,7 +190,7 @@ 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; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index f1fa5538610..9469f4c61a3 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -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",