| From | Luis Henriques <> | Subject | [PATCH 3.11 066/131] perf: Enforce 1 as lower limit for perf_event_max_sample_rate | Date | Wed, 5 Mar 2014 14:23:10 +0000 |
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3.11.10.6 -stable review patch. If anyone has any objections, please let me know.
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From: Knut Petersen <Knut_Petersen@t-online.de>
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 <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> Cc: Weng Meiling <wengmeiling.weng@huawei.com> Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- 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 f86599e..fc645f1 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -192,7 +192,7 @@ 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 07f6fc4..f252045 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", -- 1.9.0
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