>From 4ef9dabdd27a02e2ebd45c2d98afda7e43e82ab3 Mon Sep 17 00:00:00 2001 From: Knut Petersen Date: Wed, 25 Sep 2013 14:29:37 +0200 Subject: [PATCH] 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. v2: Use proc_dointvec_minmax() as suggested by Peter Zijlstra. Signed-off-by: Knut Petersen --- kernel/events/core.c | 2 +- kernel/sysctl.c | 1 + 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index dd236b6..8721a17 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -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; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index b2f06f3..2a9db91 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", -- 1.8.1.4